Multi-speed dual-clutch planetary transmissions having four fixed interconnecting members

ABSTRACT

The family of transmissions has a plurality of members that can be utilized in powertrains to provide at least six forward speed ratios and one reverse speed ratio. The transmission family members include four planetary gear sets, two input clutches, eight or nine torque transmitting mechanisms and four fixed interconnections. The invention provides a low content multi-speed dual clutch transmission mechanism wherein the two input clutches alternately connect the engine to realize odd and even number speed ratio ranges. The torque transmitting mechanisms provide connections between various gear members, the fixed interconnections, the input shaft, the output shaft, and the transmission housing, and are operated in combinations of three to establish at least five forward speed ratios and at least one reverse speed ratio.

TECHNICAL FIELD

The present invention relates to a family of power transmissions havingtwo input clutches which selectively connect an input shaft to first andsecond pairs of planetary gear sets to provide at least six forwardspeed ratios and one reverse speed ratio.

BACKGROUND OF THE INVENTION

Passenger vehicles include a powertrain that is comprised of an engine,multi-speed transmission, and a differential or final drive. Themulti-speed transmission increases the overall operating range of thevehicle by permitting the engine to operate through its torque range anumber of times.

A primary focus of transmission and engine design work is in the area ofincreasing vehicle fuel efficiency. Manual transmissions typicallyprovide improved vehicle fuel economy over automatic transmissionsbecause automatic transmissions use a torque converter for vehiclelaunch and multiple plate hydraulically-applied clutches for gearengagement. Clutches of this type, left unengaged or idling, impose aparasitic drag torque on a drive line due to the viscous shearing actionwhich exists between the plates and discs rotating at different speedsrelative to one another. This drag torque adversely affects vehicle fueleconomy for automatic transmissions. Also, the hydraulic pump thatgenerates the pressure needed for operating the above-described clutchesfurther reduces fuel efficiency associated with automatic transmissions.Manual transmissions eliminate these problems.

While manual transmissions are not subject to the above described fuelefficiency related problems, manual transmissions typically provide poorshift quality because a significant torque interruption is requiredduring each gear shift as the engine is disengaged from the transmissionby the clutch to allow shafts rotating at different speeds to besynchronized.

So called “automated manual” transmissions provide electronic shiftingin a manual transmission configuration which, in certain circumstances,improves fuel efficiency by eliminating the parasitic losses associatedwith the torque converter and hydraulic pump needed for clutching. Likemanual transmissions, a drawback of automated manual transmissions isthat the shift quality is not as high as an automatic transmissionbecause of the torque interruption during shifting.

So called “dual-clutch automatic” transmissions also eliminate thetorque converter and replace hydraulic clutches with synchronizers butthey go further to provide gear shift quality which is superior to theautomated manual transmission and similar to the conventional automatictransmission, which makes them quite attractive. However, most knowndual-clutch automatic transmissions include a lay shaft or countershaftgear arrangement, and have not been widely applied in vehicles becauseof their complexity, size and cost. For example, a dual clutch lay shafttransmission could require eight sets of gears, two input/shift clutchesand seven synchronizers/dog clutches to provide six forward speed ratiosand a reverse speed ratio. An example of a dual-clutch automatictransmission is described in U.S. Pat. No. 5,385,064, which is herebyincorporated by reference.

SUMMARY OF THE INVENTION

The invention provides a low content multi-speed dual-clutchtransmission family utilizing planetary gear sets rather than lay shaftgear arrangements. In particular, the invention includes four planetarygear sets, two input/shift clutches, and nine selectable torquetransmitting mechanisms to provide at least six forward speed ratios anda reverse speed ratio.

According to one aspect of the invention, the family of transmissionshas four planetary gear sets, each of which includes a first, second andthird member, which members may comprise a sun gear, ring gear, or aplanet carrier assembly member.

In referring to the first, second, third and fourth gear sets in thisdescription and in the claims, these sets may be counted “first” to“fourth” in any order in the drawings (i.e. left-to-right,right-to-left, etc.).

In another aspect of the present invention, each of the planetary gearsets may be of the single pinion type or of the double pinion type.

In yet another aspect of the present invention, the first member of thefirst planetary gear set is continuously connected with the first memberof the second planetary gear set through a first interconnecting member.

In yet another aspect of the present invention, the second member of thefirst planetary gear set is continuously connected with the secondmember of the second planetary gear set through a second interconnectingmember.

In yet another aspect of the present invention, a member of the first orsecond planetary gear set is continuously connected with the firstmember of the third planetary gear set and with the output shaft througha third interconnecting member.

In yet another aspect of the present invention, the second member of thethird planetary gear set is continuously connected with the first memberof the fourth planetary gear set through a fourth interconnectingmember.

In accordance with a further aspect of the invention, a first inputclutch selectively connects the input shaft with members of the first orsecond planetary gear set through other torque-transmitting mechanisms,such as rotating synchronizers.

In accordance with another aspect of the present invention, a secondinput clutch selectively connects the input shaft with the third memberof the third planetary gear set.

In another aspect of the invention, first and second torque transmittingmechanisms, such as rotating synchronizers, selectively connect membersof the first and second planetary gear sets with the first input clutch.

In still a further aspect of the invention, third and fourth torquetransmitting mechanisms, such as rotating synchronizers, selectivelyconnect members of the third planetary gear set with members of thefourth planetary gear set.

In still another aspect of the invention, fifth and sixth torquetransmitting mechanisms, such as braking synchronizers, selectivelyconnect members of the first or second planetary gear set with astationary member.

In still another aspect of the invention, seventh and eighth torquetransmitting mechanisms, such as braking synchronizers, selectivelyconnect members of the fourth planetary gear set with the stationarymember.

In still another aspect of the invention, a ninth torque transmittingmechanism, such as a rotating synchronizer, selectively connects amember of the first or second planetary gear set with another member ofthe first or second planetary gear set or with the first input clutch.Alternatively, a ninth torque transmitting mechanism, such as a brakingsynchronizer, selectively connects a member of the first or secondplanetary gear set with the transmission housing.

In accordance with a further aspect of the invention, the input clutchesand torque transmitting mechanisms are selectively engaged incombinations of at least three to provide at least six forward speedratios and a reverse speed ratio.

In accordance with a further aspect of the invention, the first inputclutch is applied for odd number speed ranges, and the second inputclutch is applied for even number speed ranges, or vice versa.

In another aspect of the invention, the first input clutch and thesecond input clutch are interchanged (i.e. alternately engaged) to shiftfrom odd number speed range to even number speed range, or vice versa.

In accordance with a further aspect of the invention, each selectedtorque transmitting mechanism for a new speed ratio is engaged prior toshifting of the input clutches to achieve shifts without torqueinterruptions.

In accordance with a further aspect of the invention, at least one pairof synchronizers is executed as a double synchronizer to reduce cost andpackage size.

In accordance with a further aspect of the invention, the first inputclutch and the first and second rotating synchronizers can be replacedwith two input clutches to further reduce content.

In accordance with a further aspect of the invention, at least one ofthe torque transmitting mechanisms can be eliminated to realize fiveforward speed ratios and a reverse speed ratio.

The above objects, features, advantages, and other objects, features,and advantages of the present invention are readily apparent from thefollowing detailed description of the best modes for carrying out theinvention when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is a schematic representation of a powertrain including aplanetary transmission incorporating a family member of the presentinvention;

FIG. 1b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 1a;

FIG. 2a is a schematic representation of a powertrain having a planetarytransmission incorporating another family member of the presentinvention;

FIG. 2b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 2a;

FIG. 3a is a schematic representation of a powertrain having a planetarytransmission incorporating another family member of the presentinvention;

FIG. 3b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 3a;

FIG. 4a is a schematic representation of a powertrain having a planetarytransmission incorporating another family member of the presentinvention;

FIG. 4b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 4a;

FIG. 5a is a schematic representation of a powertrain having a planetarytransmission incorporating another family member of the presentinvention;

FIG. 5b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 5a;

FIG. 6a is a schematic representation of a powertrain having a planetarytransmission incorporating another family member of the presentinvention;

FIG. 6b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 6a;

FIG. 7a is a schematic representation of a powertrain having a planetarytransmission incorporating another family member of the presentinvention;

FIG. 7b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 7a;

FIG. 8a is a schematic representation of a powertrain having a planetarytransmission incorporating another family member of the presentinvention;

FIG. 8b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 8a;

FIG. 9a is a schematic representation of a powertrain having a planetarytransmission incorporating another family member of the presentinvention;

FIG. 9b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 9a;

FIG. 10a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 10b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in, FIG. 10a;

FIG. 11a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 11b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 11a;

FIG. 12a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 12b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 12a;

FIG. 13a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 13b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 13a;

FIG. 14a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 14b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 14a;

FIG. 15a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

FIG. 15b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 15a;

FIG. 16a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention; and

FIG. 16b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 16a.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, wherein like characters represent the same orcorresponding parts throughout the several views, there is shown in FIG.1a a powertrain 10 having a conventional engine 12, a planetarytransmission 14, and a conventional final drive mechanism 16.

The planetary transmission 14 includes an input shaft 17 continuouslyconnected with the engine 12, a planetary gear arrangement 18, and anoutput shaft 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 18 includes four planetary gear sets20, 30, 40 and 50.

The planetary gear set 20 includes a sun gear member 22, a ring gearmember 24, and a planet carrier assembly member 26. The planet carrierassembly member 26 includes a plurality of intermeshing pinion gears 27,28 rotatably mounted on a carrier member 29 and disposed in meshingrelationship with the ring gear member 24 and the sun gear member 22,respectively.

The planetary gear set 30 includes a sun gear member 32, a ring gearmember 34, and a planet carrier assembly member 36. The planet carrierassembly member 36 includes a plurality of pinion gears 37 rotatablymounted on a carrier member 39 and disposed in meshing relationship withboth the sun gear member 32 and the ring gear member 34.

The planetary gear set 40 includes a sun gear member 42, a ring gearmember 44, and a planet carrier assembly member 46. The planet carrierassembly member 46 includes a plurality of pinion gears 47 rotatablymounted on a carrier member 49 and disposed in meshing relationship withboth the sun gear member 42 and the ring gear member 44.

The planetary gear set 50 includes a sun gear member 52, a ring gearmember 54, and a planet carrier assembly member 56. The planet carrierassembly member 56 includes a plurality of pinion gears 57 rotatablymounted on a carrier member 59 and disposed in meshing relationship withboth the sun gear member 52 and the ring gear member 54.

As a result of the dual clutch arrangement of the invention, the fourplanetary gear sets 20, 30, 40 and 50 are divided into first and secondtransmission subsets 60, 61 which are alternatively engaged to provideodd number and even number speed ranges, respectively. Transmissionsubset 60 includes planetary gear sets 20 and 30, and transmissionsubset 61 includes planetary gear sets 40 and 50. The output shaft 19 iscontinuously connected with members of both subsets 60 and 61.

As mentioned above, the first and second input clutches 62, 63 arealternatively engaged for transmitting power from the input shaft 17 totransmission subset 60 or transmission subset 61. The first and secondinput clutches 62, 63 are controlled electronically, and the disengagedinput clutch is gradually engaged while the engaged input clutch isgradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 60, 61 prior to engaging therespective input clutches 62, 63. The preselection is achieved by meansof electronically controlled synchronizers. As shown, the planetary geararrangement includes nine torque transmitting mechanisms 64, 65, 66, 67,68, 69, 70, 71 and 72. The torque transmitting mechanisms 64, 65, 66, 69and 70 comprise braking synchronizers, and the torque transmittingmechanisms 67, 68, 71 and 72 comprise rotating synchronizers.

By way of example, synchronizers which may be implemented as therotating and/or braking synchronizers referenced herein are shown in thefollowing patents, each of which are incorporated by reference in theirentirety: U.S. Pat. Nos. 5,651,435; 5,975,263; 5,560,461; 5,641,045;5,497,867; 6,354,416.

The braking synchronizers and rotating synchronizers are referenced inthe claims as follows: first and second torque transmitting mechanisms67, 68; third and fourth torque transmitting mechanisms 71, 72; fifthand sixth torque transmitting mechanisms 64, 65; seventh and eighthtorque transmitting mechanisms 69, 70; and ninth torque transmittingmechanism 66. Other family members are similarly referenced in theclaims (i.e. rotating synchronizers of left, then right, transmissionsubset; braking synchronizers of left then right transmission subsets;then ninth synchronizer).

Accordingly, the input shaft 17 is alternately connected with the firstand second transmission subsets 60, 61 (i.e. through the clutch 62 tothe synchronizers 67, 68 and through the clutch 63 to the sun gearmember 42). The sun gear member 22 is continuously connected with thering gear member 34 through the interconnecting member 74. The planetcarrier assembly member 26 is continuously connected with the sun gearmember 32 through the interconnecting member 76. The planet carrierassembly member 36 is continuously connected with the planet carrierassembly member 46 and the output shaft 19 through the interconnectingmember 78. The ring gear member 44 is continuously connected with thesun gear member 52 through the interconnecting member 79.

The ring gear member 24 is selectively connectable with the transmissionhousing 80 through the braking synchronizer 64. The ring gear member 34is selectively connectable with the transmission housing 80 through thebraking synchronizer 65. The planet carrier assembly member 26 isselectively connectable with the transmission housing 80 through thebraking synchronizer 66. The ring gear member 24 is selectivelyconnectable with the input shaft 17 through the input clutch 62 and therotating synchronizer 67. The sun gear member 32 is selectivelyconnectable with the input shaft 17 through the input clutch 62 and therotating synchronizer 68. The ring gear member 54 is selectivelyconnectable with the transmission housing 80 through the brakingsynchronizer 69. The planet carrier assembly member 56 is selectivelyconnectable with the transmission housing 80 through the brakingsynchronizer 70. The planet carrier assembly member 46 is selectivelyconnectable with the ring gear member 54 through the rotatingsynchronizer 71. The planet carrier assembly member 46 is selectivelyconnectable with the planet carrier assembly member 56 through therotating synchronizer 72.

As shown in FIG. 1b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio.

The reverse speed ratio is established with the engagement of the inputclutch 62, the braking synchronizer 64 and the rotating synchronizer 68.The input clutch 62 and the rotating synchronizer 68 connect the sungear member 32 to the input shaft 17. The braking synchronizer 64connects the ring gear member 24 to the transmission housing 80. The sungear member 22 rotates at the same speed as the ring gear member 34. Theplanet carrier assembly member 26 and the sun gear member 32 rotate atthe same speed as the input shaft 17. The ring gear member 24 does notrotate. The sun gear member 22 rotates at a speed determined from thespeed of the planet carrier assembly member 26 and the ring gear/sungear tooth ratio of the planetary gear set 20. The planet carrierassembly members 36, 46 rotate at the same speed as the output shaft 19.The planet carrier assembly member 36, and therefore the output shaft19, rotates at a speed determined from the speed of the ring gear member34, the speed of the sun gear member 32 and the ring gear/sun gear toothratio of the planetary gear set 30. The numerical value of the reversespeed ratio is determined utilizing the ring gear/sun gear tooth ratiosof the planetary gear sets 20, 30.

The first forward speed ratio is established with the engagement of theinput clutch 63, the braking synchronizer 70 and the rotatingsynchronizer 71. The input clutch 63 connects the sun gear member 42 tothe input shaft 17. The braking synchronizer 70 connects the planetcarrier assembly member 56 to the transmission housing 80. The rotatingsynchronizer 71 connects the planet carrier assembly member 46 to thering gear member 54. The sun gear member 42 rotates at the same speed asthe input shaft 17. The planet carrier assembly member 46 and the ringgear member 54 rotate at the same speed as the output shaft 19. The ringgear member 44 rotates at the same speed as the sun gear member 52. Theplanet carrier assembly member 46, and therefore the output shaft 19,rotates at a speed determined from the speed of the ring gear member 44,the speed of the sun gear member 42 and the ring gear/sun gear toothratio of the planetary gear set 40. The planet carrier assembly member56 does not rotate. The ring gear member 54 rotates at a speeddetermined from the speed of the sun gear member 52 and the ringgear/sun gear tooth ratio of the planetary gear set 50. The numericalvalue of the first forward speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 40, 50.

The second forward speed ratio is established with the engagement of theinput clutch 62, the braking synchronizer 65 and the rotatingsynchronizer 68. The input clutch 62 and the rotating synchronizer 68connect the sun gear member 32 to the input shaft 17. The brakingsynchronizer 65 connects ring gear member 34 to the transmission housing80. The sun gear member 22 and the ring gear member 34 do not rotate.The planet carrier assembly member 26 and the sun gear member 32 rotateat the same speed as the input shaft 17. The planet carrier assemblymembers 36, 46 rotate at the same speed as the output shaft 19. Theplanet carrier assembly member 36, and therefore the output shaft 19,rotates at a speed determined from the speed of the sun gear member 32and the ring gear/sun gear tooth ratio of the planetary gear set 30. Thenumerical value of the second forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratio of the planetary gear set30.

The third forward speed ratio is established with the engagement of theinput clutch 63 and the braking synchronizers 69, 70. The input clutch63 connects the sun gear member 42 to the input shaft 17. The brakingsynchronizer 69 connects the ring gear member 54 to the transmissionhousing 80. The braking synchronizer 70 connects the planet carrierassembly member 56 to the transmission housing 80. The sun gear member42 rotates at the same speed as the input shaft 17. The planet carrierassembly member 46 rotates at the same speed as the output shaft 19. Thering gear member 44 and the planetary gear set 50 do not rotate. Theplanet carrier assembly member 46, and therefore the output shaft 19,rotates at a speed determined from the speed of the sun gear member 42and the ring gear/sun gear tooth ratio of the planetary gear set 40. Thenumerical value of the third forward speed ratio is determined utilizingthe ring gear/sun gear tooth ratio of the planetary gear set 40.

The fourth forward speed ratio is established with the engagement of theinput clutch 62, the braking synchronizer 65 and the rotatingsynchronizer 67. The input clutch 62 and the rotating synchronizer 67connect the ring gear member 24 to the input shaft 17. The brakingsynchronizer 65 connects the ring gear member 34 to the transmissionhousing 80. The sun gear member 22 and the ring gear member 34 do notrotate. The planet carrier assembly member 26 rotates at the same speedas the sun gear member 32. The ring gear member 24 rotates at the samespeed as the input shaft 17. The planet carrier assembly member 26rotates at a speed determined from the speed of the ring gear member 24and the ring gear/sun gear tooth ratio of the planetary gear set 20. Theplanet carrier assembly members 36, 46 rotate at the same speed as theoutput shaft 19. The planet carrier assembly member 36, and thereforethe output shaft 19, rotates at a speed determined from the speed of thesun gear member 32 and the ring gear/sun gear tooth ratio of theplanetary gear set 30. The numerical value of the fourth forward speedratio is determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 20, 30.

The fifth forward speed ratio is established with the engagement of theinput clutch 63 and the rotating synchronizers 71, 72. In thisconfiguration, the input shaft 17 is directly connected to the outputshaft 19. The numerical value of the fifth forward speed ratio is 1.

The sixth forward speed ratio is established with the engagement of theinput clutch 62, the braking synchronizer 66 and the rotatingsynchronizer 67. The input clutch 62 and the rotating synchronizer 67connect the ring gear member 24 to the input shaft 17. The brakingsynchronizer 66 connects the planet carrier assembly member 26 to thetransmission housing 80. The sun gear member 22 rotates at the samespeed as the ring gear member 34. The planet carrier assembly member 26and the sun gear member 32 do not rotate. The ring gear member 24rotates at the same speed as the input shaft 17. The sun gear member 22rotates at a speed determined from the speed of the ring gear member 24and the ring gear/sun gear tooth ratio of the planetary gear set 20. Theplanet carrier assembly members 36, 46 rotate at the same speed as theoutput shaft 19. The planet carrier assembly member 36, and thereforethe output shaft 19, rotates at a speed determined from the speed of thering gear member 34 and the ring gear/sun gear tooth ratio of theplanetary gear set 30. The numerical value of the sixth forward speedratio is determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 20, 30.

As set forth above, the engagement schedule for the torque transmittingmechanisms is shown in the truth table of FIG. 1b. This truth table alsoprovides an example of speed ratios that are available utilizing thering gear/sun gear tooth ratios given by way of example in FIG. 1b. TheR1/S1 value is the tooth ratio of the planetary gear set 20; the R2/S2value is the tooth ratio of the planetary gear set 30; the R3/S3 valueis the tooth ratio of the planetary gear set 40; and the R4/S4 value isthe tooth ratio of the planetary gear set 50. Also, the chart of FIG. 1bdescribes the ratio steps that are attained utilizing the sample oftooth ratios given. For example, the step ratio between first and secondforward speed ratios is 1.68, while the step ratio between the reverseand first forward ratio is −0.63. Those skilled in the art willrecognize that since torque transmitting mechanisms 64 and 66 areconnected to a common member, transmission housing 80, and they are notengaged at the same time for any of the speed ratios, the pair can beexecuted as a double synchronizer to reduce content and cost. Similarly,torque transmitting mechanisms pair 70 and 72 can be executed as adouble synchronizer.

FIG. 2a shows a powertrain 110 having a conventional engine 12, aplanetary transmission 114, and a conventional final drive mechanism 16.The planetary transmission 114 includes an input shaft 17 connected withthe engine 12, a planetary gear arrangement 118, and an output shaft 19connected with the final drive mechanism 16. The planetary geararrangement 118 includes four planetary gear sets 120, 130, 140 and 150.

The planetary gear set 120 includes a sun gear member 122, a ring gearmember 124, and a planet carrier assembly member 126. The planet carrierassembly member 126 includes a plurality of pinion gears 127 rotatablymounted on a carrier member 129 and disposed in meshing relationshipwith both the sun gear member 122 and the ring gear member 124.

The planetary gear set 130 includes a sun gear member 132, a ring gearmember 134, and a planet carrier assembly member 136. The planet carrierassembly member 136 includes a plurality of intermeshing pinion gears137, 138 rotatably mounted on a carrier member 139 and disposed inmeshing relationship with the ring gear member 134 and the sun gearmember 132, respectively.

The planetary gear set 140 includes a sun gear member 142, a ring gearmember 144, and a planet carrier assembly member 146. The planet carrierassembly member 146 includes a plurality of pinion gears 147 rotatablymounted on a carrier member 149 and disposed in meshing relationshipwith both the sun gear member 142 and the ring gear member 144.

The planetary gear set 150 includes a sun gear member 152, a ring gearmember 154, and a planet carrier assembly member 156. The planet carrierassembly member 156 includes a plurality of pinion gears 157 rotatablymounted on a carrier member 159 and disposed in meshing relationshipwith both the sun gear member 152 and the ring gear member 154.

As a result of the dual clutch arrangement of the invention, the fourplanetary gear sets 120, 130, 140 and 150 are divided into first andsecond transmission subsets 160, 161 which are alternatively engaged toprovide odd number and even number speed ranges, respectively.Transmission subset 160 includes planetary gear sets 120 and 130, andtransmission subset 161 includes planetary gear sets 140 and 150. Theoutput shaft 19 is continuously connected with members of both subsets160 and 161.

As mentioned above, the first and second input clutches 162, 163 arealternatively engaged for transmitting power from the input shaft 17 totransmission subset 160 or transmission subset 161. The first and secondinput clutches 162, 163 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 160, 161 prior to engagingthe respective input clutches 162, 163. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms164, 165, 166, 167, 168, 169, 170, 171 and 172. The torque transmittingmechanisms 164, 165, 169 and 170 comprise braking synchronizers, and thetorque transmitting mechanisms 166, 167, 168, 171 and 172 compriserotating synchronizers.

Accordingly, the input shaft 17 is alternately connected with the firstand second transmission subsets 160, 161 (i.e. through the clutch 162 tosynchronizers 166, 167, 168 and through the clutch 163 to the sun gearmember 142). The planet carrier assembly member 126 is continuouslyconnected with the planet carrier assembly member 136 through theinterconnecting member 174. The ring gear member 124 is continuouslyconnected with the sun gear member 132 through the interconnectingmember 176. The ring gear member 134 is continuously connected with theplanet carrier assembly member 146 and the output shaft 19 through theinterconnecting member 178. The ring gear member 144 is continuouslyconnected with the planet carrier assembly member 156 through theinterconnecting member 179.

The sun gear member 122 is selectively connectable with the transmissionhousing 180 through the braking synchronizer 164. The planet carrierassembly member 126 is selectively connectable with the transmissionhousing 180 through the braking synchronizer 165. The sun gear member122 is selectively connectable with the input shaft 17 through the inputclutch 162 and the rotating synchronizer 166. The sun gear member 132 isselectively connectable with the input shaft 17 through the input clutch162 and the rotating synchronizer 167. The planet carrier assemblymember 126 is selectively connectable with the input shaft 17 throughthe input clutch 162 and the rotating synchronizer 168. The sun gearmember 152 is selectively connectable with the transmission housing 180through the braking synchronizer 169. The ring gear member 154 isselectively connectable with the transmission housing 180 through thebraking synchronizer 170. The planet carrier assembly member 146 isselectively connectable with the sun gear member 152 through therotating synchronizer 171. The planet carrier assembly member 146 isselectively connectable with the ring gear member 154 through therotating synchronizer 172.

As shown in FIG. 2b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio.

The reverse speed ratio is established with the engagement of the inputclutch 162, the braking synchronizer 165 and the rotating synchronizer166. The input clutch 162 and the rotating synchronizer 166 connect thesun gear member 122 to the input shaft 17. The braking synchronizer 165connects the planet carrier assembly member 126 to the transmissionhousing 180. The sun gear member 122 rotates at the same speed as theinput shaft 17. The planet carrier assembly member 126 and the planetcarrier assembly member 136 do not rotate. The ring gear member 124rotates at the same speed as the sun gear member 132. The ring gearmember 124 rotates at a speed determined from the speed of the sun gearmember 122 and the ring gear/sun gear tooth ratio of the planetary gearset 120. The ring gear member 134 and the planet carrier assembly member146 rotate at the same speed as the output shaft 19. The ring gearmember 134, and therefore the output shaft 19, rotates at a speeddetermined from the speed of the sun gear member 132 and the ringgear/sun gear tooth ratio of the planetary gear set 130. The numericalvalue of the reverse speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 120, 130.

The first forward speed ratio is established with the engagement of theinput clutch 163 and the braking synchronizers 169, 170. The inputclutch 163 connects the sun gear member 142 to the input shaft 17. Thebraking synchronizer 169 connects the sun gear member 152 to thetransmission housing 180. The braking synchronizer 170 connects the ringgear member 154 to the transmission housing 180. The sun gear member 142rotates at the same speed as the input shaft 17. The planet carrierassembly member 146 rotates at the same speed as the output shaft 19.The ring gear member 144 and the planetary gear set 150 do not rotate.The planet carrier assembly member 146, and therefore the output shaft19, rotates at a speed determined from the speed of the sun gear member142 and the ring gear/sun gear tooth ratio of the planetary gear set140. The numerical value of the first forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratio of the planetary gear set140.

The second forward speed ratio is established with the engagement of theinput clutch 162, the braking synchronizer 165 and the rotatingsynchronizer 167. The input clutch 162 and the rotating synchronizer 167connect the sun gear member 132 to the input shaft 17. The brakingsynchronizer 165 connects the planet carrier assembly member 126 to thetransmission housing 180. The planet carrier assembly member 126 and theplanet carrier assembly member 136 do not rotate. The ring gear member124 and the sun gear member 132 rotate at the same speed as the inputshaft 17. The ring gear member 134 and the planet carrier assemblymember 146 rotate at the same speed as the output shaft 19. The ringgear member 134, and therefore the output shaft 19, rotates at a speeddetermined from the speed of the sun gear member 132 and the ringgear/sun gear tooth ratio of the planetary gear set 130. The numericalvalue of the second forward speed ratio is determined utilizing the ringgear/sun gear tooth ratio of the planetary gear set 130.

The third forward speed ratio is established with the engagement of theinput clutch 163, the braking synchronizer 169 and the rotatingsynchronizer 172. The input clutch 163 connects the sun gear member 142to the input shaft 17. The braking synchronizer 169 connects the sungear member 152 to the transmission housing 180. The rotatingsynchronizer 172 connects the planet carrier assembly member 146 to thering gear member 154. The sun gear member 142 rotates at the same speedas the input shaft 17. The planet carrier assembly member 146 and thering gear member 154 rotate at the same speed as the output shaft 19.The ring gear member 144 rotates at the same speed as the planet carrierassembly member 156. The planet carrier assembly member 146, andtherefore the output shaft 19, rotates at a speed determined from thespeed of the ring gear member 144, the speed of the sun gear member 142and the ring gear/sun gear tooth ratio of the planetary gear set 140.The sun gear member 152 does not rotate. The ring gear member 154rotates at a speed determined from the speed of the planet carrierassembly member 156 and the ring gear/sun gear tooth ratio of theplanetary gear set 150. The numerical value of the third forward speedratio is determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 140, 150.

The fourth forward speed ratio is established with the engagement of theinput clutch 162, the braking synchronizer 164 and the rotatingsynchronizer 167. The input clutch 162 and the rotating synchronizer 167connect the sun gear member 132 to the input shaft 17. The brakingsynchronizer 164 connects the sun gear member 122 to the transmissionhousing 180. The sun gear member 122 does not rotate. The planet carrierassembly member 126 rotates at the same speed as the planet carrierassembly member 136. The ring gear member 124 and the sun gear member132 rotate at the same speed as the input shaft 17. The planet carrierassembly member 126 rotates at a speed determined from the speed of thering gear member 124 and the ring gear/sun gear tooth ratio of theplanetary gear set 120. The ring gear member 134 and the planet carrierassembly member 146 rotate at the same speed as the output shaft 19. Thering gear member 134, and therefore the output shaft 19, rotates at aspeed determined from the speed of the planet carrier assembly member136, the speed of the sun gear member 132 and the ring gear/sun geartooth ratio of the planetary gear set 130. The numerical value of thefourth forward speed ratio is determined utilizing the ring gear/sungear tooth ratios of the planetary gear sets 120, 130.

The fifth forward speed ratio is established with the engagement of theinput clutch 163 and the rotating synchronizers 171, 172. In thisconfiguration, the input shaft 17 is directly connected to the outputshaft 19. The numerical value of the fifth forward speed ratio is 1.

The sixth forward speed ratio is established with the engagement of theinput clutch 162, the braking synchronizer 164 and the rotatingsynchronizer 168. The input clutch 162 and the rotating synchronizer 168connect the planet carrier assembly member 126 to the input shaft 17.The braking synchronizer 164 connects the sun gear member 122 to thetransmission housing 180. The sun gear member 122 does not rotate. Theplanet carrier assembly members 126, 136 rotate at the same speed as theinput shaft 17. The ring gear member 124 rotates at the same speed asthe sun gear member 132. The ring gear member 124 rotates at a speeddetermined from the speed of the planet carrier assembly member 126 andthe ring gear/sun gear tooth ratio of the planetary gear set 120. Thering gear member 134 and the planet carrier assembly member 146 rotateat the same speed as the output shaft 19. The ring gear member 134, andtherefore the output shaft 19, rotates at a speed determined from thespeed of the planet carrier assembly member 136, the speed of the sungear member 132 and the ring gear/sun gear tooth ratio of the planetarygear set 130. The numerical value of the sixth forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 120, 130.

As set forth above, the truth table of FIG. 2b describes the engagementsequence of the torque transmitting mechanisms utilized to provide areverse drive ratio and six forward speed ratios. The truth table alsoprovides an example of the ratios that can be attained with the familymembers shown in FIG. 2a utilizing the sample tooth ratios given in FIG.2b. The R1/S1 value is the tooth ratio of the planetary gear set 120;the R2/S2 value is the tooth ratio of the planetary gear set 130; theR3/S3 value is the tooth ratio of the planetary gear set 140; and theR4/S4 value is the tooth ratio of the planetary gear set 150. Also shownin FIG. 2b are the ratio steps between single step ratios in the forwarddirection as well as the reverse to first ratio step. For example, thefirst to second step ratio is 1.67. Those skilled in the art willrecognize that since torque transmitting mechanisms 164 and 165 areconnected to a common member, transmission housing 180, and they are notengaged at the same time for any of the speed ratios, the pair can beexecuted as a double synchronizer to reduce content and cost. Similarly,torque transmitting mechanisms pair 170 and 172 can be executed as adouble synchronizer.

Turning the FIG. 3a, a powertrain 210 having a conventional engine 12, aplanetary transmission 214, and conventional final drive mechanism 16 isshown.

The planetary transmission 214 includes an input shaft 17 continuouslyconnected with the engine 12, a planetary gear arrangement 218, and anoutput shaft 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 218 includes four planetary gear sets220, 230, 240 and 250.

The planetary gear set 220 includes a sun gear member 222, a ring gearmember 224, and a planet carrier assembly member 226. The planet carrierassembly member 226 includes a plurality of intermeshing pinion gears227, 228 rotatably mounted on a carrier member 229 and disposed inmeshing relationship with the ring gear member 224 and the sun gearmember 222, respectively.

The planetary gear set 230 includes a sun gear member 232, a ring gearmember 234, and a planet carrier assembly member 236. The planet carrierassembly member 236 includes a plurality of pinion gears 237 rotatablymounted on a carrier member 239 and disposed in meshing relationshipwith both the sun gear member 232 and the ring gear member 234.

The planetary gear set 240 includes a sun gear member 242, a ring gearmember 244, and a planet carrier assembly member 246. The planet carrierassembly member 246 includes a plurality of pinion gears 247 rotatablymounted on a carrier member 249 and disposed in meshing relationshipwith both the sun gear member 242 and the ring gear member 244.

The planetary gear set 250 includes a sun gear member 252, a ring gearmember 254, and a planet carrier assembly member 256. The planet carrierassembly member 256 includes a plurality of pinion gears 257 rotatablymounted on a carrier member 259 and disposed in meshing relationshipwith both the sun gear member 252 and the ring gear member 254.

As a result of the dual clutch arrangement of the invention, the fourplanetary gear sets 220, 230, 240 and 250 are divided into first andsecond transmission subsets 260, 261 which are alternatively engaged toprovide odd number and even number speed ranges, respectively.Transmission subset 260 includes planetary gear sets 220 and 230, andtransmission subset 261 includes planetary gear sets 240 and 250. Theoutput shaft 19 is continuously connected with members of both subsets260 and 261.

As mentioned above, the first and second input clutches 262, 263 arealternatively engaged for transmitting power from the input shaft 17 totransmission subset 260 or transmission subset 261. The first and secondinput clutches 262, 263 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 260, 261 prior to engagingthe respective input clutches 262, 263. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms264, 265, 266, 267, 268, 269, 270, 271 and 272. The torque transmittingmechanisms 264, 265, 266, 269 and 270 comprise braking synchronizers,and the torque transmitting mechanisms 267, 268, 271 and 272 compriserotating synchronizers.

Accordingly, the input shaft 17 is alternately connected with the firstand second transmission subsets 260, 261 (i.e. through the clutch 262 tosynchronizers 267, 268 and through the clutch 263 to the sun gear member242). The sun gear member 222 is continuously connected with the ringgear member 234 through the interconnecting member 274. The planetcarrier assembly member 226 is continuously connected with the sun gearmember 232 through the interconnecting member 276. The planet carrierassembly member 246 is continuously connected with the planet carrierassembly member 236 and the output shaft 19 through the interconnectingmember 278. The ring gear member 244 is continuously connected with theplanet carrier assembly member 256 through the interconnecting member279.

The ring gear member 224 is selectively connectable with thetransmission housing 280 through the braking synchronizer 264. The ringgear member 234 is selectively connectable with the transmission housing280 through the braking synchronizer 265. The planet carrier assemblymember 226 is selectively connectable with the transmission housing 280through the braking synchronizer 266. The ring gear member 224 isselectively connectable with the input shaft 17 through the input clutch262 and the rotating synchronizer 267. The sun gear member 232 isselectively connectable with the input shaft 17 through the input clutch262 and the rotating synchronizer 268. The sun gear member 252 isselectively connectable with the transmission housing 280 through thebraking synchronizer 269. The ring gear member 254 is selectivelyconnectable with the transmission housing 280 through the brakingsynchronizer 270. The planet carrier assembly member 246 is selectivelyconnectable with the sun gear member 252 through the rotatingsynchronizer 271. The planet carrier assembly member 246 is selectivelyconnectable with the ring gear member 254 through the rotatingsynchronizer 272.

As shown in FIG. 3b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio.

The reverse speed ratio is established with the engagement of the inputclutch 262, the braking synchronizer 264 and the rotating synchronizer268. The input clutch 262 and the rotating synchronizer 268 connect thesun gear member 232 to the input shaft 17. The braking synchronizer 264connects the ring gear member 224 to the transmission housing 280. Thesun gear member 222 rotates at the same speed as the ring gear member234. The planet carrier assembly member 226 and the sun gear member 232rotate at the same speed as the input shaft 17. The ring gear member 224does not rotate. The sun gear member 222 rotates at a speed determinedfrom the speed of the planet carrier assembly member 226 and the ringgear/sun gear tooth ratio of the planetary gear set 220. The planetcarrier assembly members 236, 246 rotate at the same speed as the outputshaft 19. The planet carrier assembly member 236, and therefore theoutput shaft 19, rotates at a speed determined from the speed of thering gear member 234, the speed of the sun gear member 232 and the ringgear/sun gear tooth ratio of the planetary gear set 230. The numericalvalue of the reverse speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 220, 230.

The first forward speed ratio is established with the engagement of theinput clutch 263 and the braking synchronizers 269, 270. The inputclutch 263 connects the sun gear member 242 to the input shaft 17. Thebraking synchronizer 269 connects the sun gear member 252 to thetransmission housing 280. The braking synchronizer 270 connects the ringgear member 254 to the transmission housing 280. The sun gear member 242rotates at the same speed as the input shaft 17. The planet carrierassembly member 246 rotates at the same speed as the output shaft 19.The ring gear member 244 and the planetary gear set 250 do not rotate.The planet carrier assembly member 246, and therefore the output shaft19, rotates at a speed determined from the speed of the sun gear member242 and the ring gear/sun gear tooth ratio of the planetary gear set240. The numerical value of the first forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratio of the planetary gear set240.

The second forward speed ratio is established with the engagement of theinput clutch 262, the braking synchronizer 265 and the rotatingsynchronizer 268. The input clutch 262 and the rotating synchronizer 268connect the sun gear member 232 to the input shaft 17. The brakingsynchronizer 265 connects the ring gear member 234 to the transmissionhousing 280. The sun gear member 222 and the ring gear member 234 do notrotate. The planet carrier assembly member 226 and the sun gear member232 rotate at the same speed as the input shaft 17. The planet carrierassembly members 236, 246 rotate at the same speed as the output shaft19. The planet carrier assembly member 236, and therefore the outputshaft 19, rotates at a speed determined from the speed of the sun gearmember 232 and the ring gear/sun gear tooth ratio of the planetary gearset 230. The numerical value of the second forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratio of the planetarygear set 230.

The third forward speed ratio is established with the engagement of theinput clutch 263, the braking synchronizer 269 and the rotatingsynchronizer 272. The input clutch 263 connects the sun gear member 242to the input shaft 17. The braking synchronizer 269 connects the sungear member 252 to the transmission housing 280. The rotatingsynchronizer 272 connects the planet carrier assembly member 246 to thering gear member 254. The sun gear member 242 rotates at the same speedas the input shaft 17. The planet carrier assembly member 246 and thering gear member 254 rotate at the same speed as the output shaft 19.The ring gear member 244 rotates at the same speed as the planet carrierassembly member 256. The planet carrier assembly member 246, andtherefore the output shaft 19, rotates at a speed determined from thespeed of the ring gear member 244, the speed of the sun gear member 242and the ring gear/sun gear tooth ratio of the planetary gear set 240.The sun gear member 252 does not rotate. The ring gear member 254rotates at a speed determined from the speed of the planet carrierassembly member 256 and the ring gear/sun gear tooth ratio of theplanetary gear set 250. The numerical value of the third forward speedratio is determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 240, 250.

The fourth forward speed ratio is established with the engagement of theinput clutch 262, the braking synchronizer 265 and the rotatingsynchronizer 267. The input clutch 262 and the rotating synchronizer 267connect the ring gear member 224 to the input shaft 17. The brakingsynchronizer 265 connects the ring gear member 234 to the transmissionhousing 280. The sun gear member 222 and the ring gear member 234 do notrotate. The planet carrier assembly member 226 rotates at the same speedas the sun gear member 232. The ring gear member 224 rotates at the samespeed as the input shaft 17. The planet carrier assembly member 226rotates at a speed determined from the speed of the ring gear member 224and the ring gear/sun gear tooth ratio of the planetary gear set 220.The planet carrier assembly members 236, 246 rotate at the same speed asthe output shaft 19. The planet carrier assembly member 236, andtherefore the output shaft 19, rotates at a speed determined from thespeed of the sun gear member 232 and the ring gear/sun gear tooth ratioof the planetary gear set 230. The numerical value of the fourth forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratiosof the planetary gear sets 220, 230.

The fifth forward speed ratio is established with the engagement of theinput clutch 263 and the rotating synchronizers 271, 272. In thisconfiguration, the input shaft 17 is directly connected to the outputshaft 19. The numerical value of the fifth forward speed ratio is 1.

The sixth forward speed ratio is established with the engagement of theinput clutch 262, the braking synchronizer 266 and the rotatingsynchronizer 267. The input clutch 262 and the rotating synchronizer 267connect the ring gear member 224 to the input shaft 17. The brakingsynchronizer 266 connects the planet carrier assembly member 226 to thetransmission housing 280. The sun gear member 222 rotates at the samespeed as the ring gear member 234. The planet carrier assembly member226 and the sun gear member 232 do not rotate. The ring gear member 224rotates at the same speed as the input shaft 17. The sun gear member 222rotates at a speed determined from the speed of the ring gear member 224and the ring gear/sun gear tooth ratio of the planetary gear set 220.The planet carrier assembly members 236, 246 rotate at the same speed asthe output shaft 19. The planet carrier assembly member 236, andtherefore the output shaft 19, rotates at a speed determined from thespeed of the ring gear member 234 and the ring gear/sun gear tooth ratioof the planetary gear set 230. The numerical value of the sixth forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratiosof the planetary gear sets 220, 230.

As previously set forth, the truth table of FIG. 3b describes thecombinations of engagements utilized for six forward speed ratios andone reverse speed ratio. The truth table also provides an example ofspeed ratios that are available with the family member described above.These examples of speed ratios are determined the tooth ratios given inFIG. 3b. The R1/S1 value is the tooth ratio of the planetary gear set220; the R2/S2 value is the tooth ratio of the planetary gear set 230;the R3/S3 value is the tooth ratio of the planetary gear set 240; andthe R4/S4 value is the tooth ratio of the planetary gear set 250. Alsodepicted in FIG. 3b is a chart representing the ratio steps betweenadjacent forward speed ratios and the reverse speed ratio. For example,the first to second ratio interchange has a step of 1.59.

A powertrain 310, shown in FIG. 4a, includes the engine 12, a planetarytransmission 314, and the final drive mechanism 16. The planetarytransmission 314 includes an input shaft 17 continuously connected withthe engine 12, a planetary gear arrangement 318, and an output shaft 19continuously connected with the final drive mechanism 16. The planetarygear arrangement 318 includes four planetary gear sets 320, 330, 340 and350.

The planetary gear set 320 includes a sun gear member 322, a ring gearmember 324, and a planet carrier assembly member 326. The planet carrierassembly member 326 includes a plurality of intermeshing pinion gears327, 328 rotatably mounted on a carrier member 329 and disposed inmeshing relationship with the ring gear member 324 and the sun gearmember 322, respectively.

The planetary gear set 330 includes a sun gear member 332, a ring gearmember 334, and a planet carrier assembly member 336. The planet carrierassembly member 336 includes a plurality of pinion gears 337 rotatablymounted on a carrier member 339 and disposed in meshing relationshipwith both the sun gear member 332 and the ring gear member 334.

The planetary gear set 340 includes a sun gear member 342, a ring gearmember 344, and a planet carrier assembly member 346. The planet carrierassembly member 346 includes a plurality of pinion gears 347 rotatablymounted on a carrier member 349 and disposed in meshing relationshipwith both the sun gear member 342 and the ring gear member 344.

The planetary gear set 350 includes a sun gear member 352, a ring gearmember 354, and a planet carrier assembly member 356. The planet carrierassembly member 356 includes a plurality of pinion gears 357 rotatablymounted on a carrier member 359 and disposed in meshing relationshipwith both the sun gear member 352 and the ring gear member 354.

As a result of the dual clutch arrangement of the invention, the fourplanetary gear sets 320, 330, 340 and 350 are divided into first andsecond transmission subsets 360, 361 which are alternatively engaged toprovide odd number and even number speed ranges, respectively.Transmission subset 360 includes planetary gear sets 320 and 330, andtransmission subset 361 includes planetary gear sets 340 and 350. Theoutput shaft 19 is continuously connected with members of both subsets360 and 361.

As mentioned above, the first and second input clutches 362, 363 arealternatively engaged for transmitting power from the input shaft 17 totransmission subset 360 or transmission subset 361. The first and secondinput clutches 362, 363 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 360, 361 prior to engagingthe respective input clutches 362, 363. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms364, 365, 366, 367, 368, 369, 370, 371 and 372. The torque transmittingmechanisms 364, 365, 366, 369 and 370 comprise braking synchronizers,and the torque transmitting mechanisms 367, 368, 371 and 372 comprisesynchronizers.

Accordingly, the input shaft 17 is alternately connected with the firstand second transmission subsets 360, 361 (i.e. through the clutch 362 tosynchronizers 367, 368 and through the clutch 363 to the ring gearmember 344). The sun gear member 322 is continuously connected with thering gear member 334 through the interconnecting member 374. The planetcarrier assembly member 326 is continuously connected with the sun gearmember 332 through the interconnecting member 376. The planet carrierassembly member 346 is continuously connected with the planet carrierassembly member 336 and the output shaft 19 through the interconnectingmember 378. The sun gear member 342 is continuously connected with thering gear member 354 through the interconnecting member 379.

The ring gear member 324 is selectively connectable with thetransmission housing 380 through the braking synchronizer 364. The ringgear member 334 is selectively connectable with the transmission housing380 through the braking synchronizer 365. The planet carrier assemblymember 326 is selectively connectable with the transmission housing 380through the braking synchronizer 366. The ring gear member 324 isselectively connectable with the input shaft 17 through the input clutch362 and the rotating synchronizer 367. The sun gear member 332 isselectively connectable with the input shaft 17 through the input clutch362 and the rotating synchronizer 368. The planet carrier assemblymember 356 is selectively connectable with the transmission housing 380through the braking synchronizer 369. The sun gear member 352 isselectively connectable with the transmission housing 380 through thebraking synchronizer 370. The planet carrier assembly member 346 isselectively connectable with the planet carrier assembly member 356through the rotating synchronizer 371. The planet carrier assemblymember 346 is selectively connectable with the sun gear member 352through the rotating synchronizer 372.

The truth tables given in FIGS. 4b, 5 b, 6 b, 7 b, 8 b, 9 b, 10 b, 11 b,12 b, 13 b, 14 b, 15 b and 16 b show the engagement sequences for thetorque transmitting mechanisms to provide at least five forward speedratios and one reverse speed ratio. As shown and described above for theconfigurations in FIGS. 1a, 2 a and 3 a, those skilled in the art willunderstand from the respective truth tables how the speed ratios areestablished through the planetary gear sets identified in the writtendescription.

The truth table shown in FIG. 4b describes the engagement combinationand engagement sequence necessary to provide the reverse drive ratio andsix forward speed ratios. A sample of the numerical values for theratios is also provided in the truth table of FIG. 4b. These values aredetermined utilizing the ring gear/sun gear tooth ratios also given inFIG. 4b. The R1/S1 value is the tooth ratio for the planetary gear set320; the R2/S2 value is the tooth ratio for the planetary gear set 330;the R3/S3 value is the tooth ratio for the planetary gear set 340; andthe R4/S4 value is the tooth ratio for the planetary gear set 350. Alsogiven in FIG. 4b is a chart describing the step ratios between theadjacent forward speed ratios and the reverse to first forward speedratio. For example, the first to second forward speed ratio step is1.62.

Those skilled in the art will recognize that the numerical values of thereverse, third and fifth forward speed ratios are determined utilizingthe ring gear/sun gear tooth ratios of the planetary gear sets 320, 330.The numerical value of the first forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratio of the planetary gear set330. The numerical values of the second and sixth forward speed ratiosare determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 340, 350. The numerical value of the fourth forwardspeed ratio is 1.

A powertrain 410 shown in FIG. 5a includes a conventional engine 12, aplanetary transmission 414, and a conventional final drive mechanism 16.The planetary transmission 414 includes an input shaft 17 connected withthe engine 12, a planetary gear arrangement 418, and an output shaft 19continuously connected with the final drive mechanism 16. The planetarygear arrangement 418 includes four planetary gear sets 420, 430, 440 and450.

The planetary gear set 420 includes a sun gear member 422, a ring gearmember 424, and a planet carrier assembly member 426. The planet carrierassembly member 426 includes a plurality of intermeshing pinion gears427, 428 rotatably mounted on a carrier member 429 and disposed inmeshing relationship with the ring gear member 424 and the sun gearmember 422, respectively.

The planetary gear set 430 includes a sun gear member 432, a ring gearmember 434, and a planet carrier assembly member 436. The planet carrierassembly member 436 includes a plurality of pinion gears 437 rotatablymounted on a carrier member 439 and disposed in meshing relationshipwith both the sun gear member 432 and the ring gear member 434.

The planetary gear set 440 includes a sun gear member 442, a ring gearmember 444, and a planet carrier assembly member 446. The planet carrierassembly member 446 includes a plurality of pinion gears 447 rotatablymounted on a carrier member 449 and disposed in meshing relationshipwith both the sun gear member 442 and the ring gear member 444.

The planetary gear set 450 includes a sun gear member 452, a ring gearmember 454, and a planet carrier assembly member 456. The planet carrierassembly member 456 includes a plurality of pinion gears 457 rotatablymounted on a carrier member 459 and disposed in meshing relationshipwith both the sun gear member 452 and the ring gear member 454.

As a result of the dual clutch arrangement of the invention, the fourplanetary gear sets 420, 430, 440 and 450 are divided into first andsecond transmission subsets 460, 461 which are alternatively engaged toprovide odd number and even number speed ranges, respectively.Transmission subset 460 includes planetary gear sets 420 and 430, andtransmission subset 461 includes planetary gear sets 440 and 450. Theoutput shaft 19 is continuously connected with members of both subsets460 and 461.

As mentioned above, the first and second input clutches 462, 463 arealternatively engaged for transmitting power from the input shaft 17 totransmission subset 460 or transmission subset 461. The first and secondinput clutches 462, 463 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 460, 461 prior to engagingthe respective input clutches 462, 463. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms464, 465, 466, 467, 468, 469, 470, 471 and 472. The torque transmittingmechanisms 464, 465, 469 and 470 comprise braking synchronizers, and thetorque transmitting mechanisms 466, 467, 468, 471 and 472 compriserotating synchronizers.

Accordingly, the input shaft 17 is alternately connected with the firstand second transmission subsets 460, 461 (i.e. through the clutch 462 tothe synchronizers 466, 467, 468 and through the clutch 463 to the sungear member 442). The ring gear member 424 is continuously connectedwith the planet carrier assembly member 436 through the interconnectingmember 474. The planet carrier assembly member 426 is continuouslyconnected with the sun gear member 432 through the interconnectingmember 476. The planet carrier assembly member 446 is continuouslyconnected with the ring gear member 434 and the output shaft 19 throughthe interconnecting member 478. The ring gear member 444 is continuouslyconnected with the planet carrier assembly member 456 through theinterconnecting member 479.

The planet carrier assembly member 426 is selectively connectable withthe transmission housing 480 through the braking synchronizer 464. Thering gear member 424 is selectively connectable with the transmissionhousing 480 through the braking synchronizer 465. The planet carrierassembly member 426 is selectively connectable with the input shaft 17through the input clutch 462 and the rotating synchronizer 466. The sungear member 422 is selectively connectable with the input shaft 17through the input clutch 462 and the rotating synchronizer 467. Theplanet carrier assembly member 436 is selectively connectable with theinput shaft 17 through the input clutch 462 and the rotatingsynchronizer 468. The sun gear member 452 is selectively connectablewith the transmission housing 480 through the braking synchronizer 469.The ring gear member 454 is selectively connectable with thetransmission housing 480 through the braking synchronizer 470. Theplanet carrier assembly member 446 is selectively connectable with thesun gear member 452 through the rotating synchronizer 471. The planetcarrier assembly member 446 is selectively connectable with the ringgear member 454 through the rotating synchronizer 472.

As shown in FIG. 5b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio.

FIG. 5b also provides a chart of the ratio steps between adjacentforward ratios and between the reverse and first ratio. For example, theratio step between the first and second forward ratios is 1.51. Thoseskilled in the art will recognize that the numerical values of thereverse and sixth forward speed ratios are determined utilizing the ringgear/sun gear tooth ratio of the planetary gear set 430. The numericalvalue of the first forward speed ratio is determined utilizing the ringgear/sun gear tooth ratio of the planetary gear set 440. The numericalvalues of the second and fourth forward speed ratios are determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets420, 430. The numerical value of the third forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 440, 450. The numerical value of the fifth forwardspeed ratio is 1.

A powertrain 510, shown in FIG. 6a, includes a conventional engine 12, apowertrain 514, and a conventional final drive mechanism 16. Thepowertrain 514 includes an input shaft 17 connected with the engine 12,a planetary gear arrangement 518, and an output shaft 19 continuouslyconnected with the final drive mechanism 16. The planetary geararrangement 518 includes four planetary gear sets 520, 530, 540 and 550.

The planetary gear set 520 includes a sun gear member 522, a ring gearmember 524, and a planet carrier assembly member 526. The planet carrierassembly member 526 includes a plurality of pinion gears 527 rotatablymounted on a carrier member 529 and disposed in meshing relationshipwith both the sun gear member 522 and the ring gear member 524.

The planetary gear set 530 includes a sun gear member 532, a ring gearmember 534, and a planet carrier assembly member 536. The planet carrierassembly member 536 includes a plurality of intermeshing pinion gears537, 538 rotatably mounted on a carrier member 539 and disposed inmeshing relationship with the ring gear member 534 and the sun gearmember 532, respectively.

The planetary gear set 540 includes a sun gear member 542, a ring gearmember 544, and a planet carrier assembly member 546. The planet carrierassembly member 546 includes a plurality of pinion gears 547 rotatablymounted on a carrier member 549 and disposed in meshing relationshipwith both the sun gear member 542 and the ring gear member 544.

The planetary gear set 550 includes a sun gear member 552, a ring gearmember 554, and a planet carrier assembly member 556. The planet carrierassembly member 556 includes a plurality of pinion gears 557 rotatablymounted on a carrier member 559 and disposed in meshing relationshipwith both the sun gear member 552 and the ring gear member 554.

As a result of the dual clutch arrangement of the invention, the fourplanetary gear sets 520, 530, 540 and 550 are divided into first andsecond transmission subsets 560, 561 which are alternatively engaged toprovide odd number and even number speed ranges, respectively.Transmission subset 560 includes planetary gear sets 520 and 530, andtransmission subset 561 includes planetary gear sets 540 and 550. Theoutput shaft 19 is continuously connected with members of both subsets560 and 561.

As mentioned above, the first and second input clutches 562, 563 arealternatively engaged for transmitting power from the input shaft 17 totransmission subset 560 or transmission subset 561. The first and secondinput clutches 562, 563 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 560, 561 prior to engagingthe respective input clutches 562, 563. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms564, 565, 566, 567, 568, 569, 570, 571 and 572. The torque transmittingmechanisms 564, 565, 569 and 570 comprise braking synchronizers, and thetorque transmitting mechanisms 566, 567, 568, 571 and 572 compriserotating synchronizers.

Accordingly, the input shaft 17 is alternately connected with the firstand second transmission subsets 560, 561 (i.e. through the clutch 562 tosynchronizers 566, 567, 568 and through the clutch 563 to the ring gearmember 544). The planet carrier assembly member 526 is continuouslyconnected with the planet carrier assembly member 536 through theinterconnecting member 574. The ring gear member 524 is continuouslyconnected with the sun gear member 532 through the interconnectingmember 576. The planet carrier assembly member 546 is continuouslyconnected with the ring gear member 534 and the output shaft 19 throughthe interconnecting member 578. The sun gear member 542 is continuouslyconnected with the ring gear member 554 through the interconnectingmember 579.

The sun gear member 522 is selectively connectable with the transmissionhousing 580 through the braking synchronizer 564. The planet carrierassembly member 536 is selectively connectable with the transmissionhousing 580 through the braking synchronizer 565. The sun gear member522 is selectively connectable with the input shaft 17 through the inputclutch 562 and the rotating synchronizer 566. The ring gear member 524is selectively connectable with the input shaft 17 through the inputclutch 562 and the rotating synchronizer 567. The planet carrierassembly member 536 is selectively connectable with the input shaft 17through the input clutch 562 and the rotating synchronizer 568. Theplanet carrier assembly member 556 is selectively connectable with thetransmission housing 580 through the braking synchronizer 569. The sungear member 552 is selectively connectable with the transmission housing580 through the braking synchronizer 570. The planet carrier assemblymember 546 is selectively connectable with the planet carrier assemblymember 556 through the rotating synchronizer 571. The planet carrierassembly member 546 is selectively connectable with the sun gear member552 through the rotating synchronizer 572.

As shown in FIG. 6b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio. The chart of FIG. 6b describesthe ratio steps between adjacent forward speed ratios and the ratio stepbetween the reverse and first forward speed ratio.

Those skilled in the art, upon reviewing the truth table and theschematic representation of FIG. 6a can determine that the numericalvalues of the reverse, third and fifth forward speed ratios aredetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 520, 530. The numerical value of the first forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratioof the planetary gear set 530. The numerical values of the second andsixth forward speed ratios are determined utilizing the ring gear/sungear tooth ratios of the planetary gear sets 540, 550. The numericalvalue of the fourth forward speed ratio is 1.

The sample speed ratios given in the truth table are determinedutilizing the tooth ratio values also given in FIG. 6b. R1/S1 value isthe tooth ratio of the planetary gear set 520; the R2/S2 value is thetooth ratio of the planetary gear set 530; the R3/S3 value is the toothratio of the planetary gear set 540; and the R4/S4 value is the toothratio of the planetary gear set 550.

A powertrain 610, shown in FIG. 7a, has the engine 12, a planetarytransmission 614, and the final drive mechanism 16. The planetarytransmission 614 includes the input shaft 17, a planetary geararrangement 618, and the output shaft 19. The planetary gear arrangement618 includes four planetary gear sets 620, 630, 640 and 650.

The planetary gear set 620 includes a sun gear member 622, a ring gearmember 624, and a planet carrier assembly member 626. The planet carrierassembly member 626 includes a plurality of intermeshing pinion gears627, 628 rotatably mounted on a carrier member 629 and disposed inmeshing relationship with the ring gear member 624 and the sun gearmember 622, respectively.

The planetary gear set 630 includes a sun gear member 632, a ring gearmember 634, and a planet carrier assembly member 636. The planet carrierassembly member 636 includes a plurality of pinion gears 637 rotatablymounted on a carrier member 639 and disposed in meshing relationshipwith both the sun gear member 632 and the ring gear member 634.

The planetary gear set 640 includes a sun gear member 642, a ring gearmember 644, and a planet carrier assembly member 646. The planet carrierassembly member 646 includes a plurality of intermeshing pinion gears647, 648 rotatably mounted on a carrier member 649 and disposed inmeshing relationship with the ring gear member 644 and the sun gearmember 642, respectively.

The planetary gear set 650 includes a sun gear member 652, a ring gearmember 654, and a planet carrier assembly member 656. The planet carrierassembly member 656 includes a plurality of pinion gears 657 rotatablymounted on a carrier member 659 and disposed in meshing relationshipwith both the sun gear member 652 and the ring gear member 654.

As a result of the dual clutch arrangement of the invention, the fourplanetary gear sets 620, 630, 640 and 650 are divided into first andsecond transmission subsets 660, 661 which are alternatively engaged toprovide odd number and even number speed ranges, respectively.Transmission subset 660 includes planetary gear sets 620 and 630, andtransmission subset 661 includes planetary gear sets 640 and 650. Theoutput shaft 19 is continuously connected with members of both subsets660 and 661.

As mentioned above, the first and second input clutches 662, 663 arealternatively engaged for transmitting power from the input shaft 17 totransmission subset 660 or transmission subset 661. The first and secondinput clutches 662, 663 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 660, 661 prior to engagingthe respective input clutches 662, 663. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms664, 665, 666, 667, 668, 669, 670, 671 and 672. The torque transmittingmechanisms 664, 665, 666, 669 and 670 comprise braking synchronizers,and the torque transmitting mechanisms 667, 668, 671 and 672 compriserotating synchronizers.

Accordingly, the input shaft 17 is alternately connected with the firstand second transmission subsets 660, 661 (i.e. through the clutch 662 tosynchronizers 667, 668 and through the clutch 663 to the ring gearmember 644). The sun gear member 622 is continuously connected with thering gear member 634 through the interconnecting member 674. The planetcarrier assembly member 626 is continuously connected with the sun gearmember 632 through the interconnecting member 676. The planet carrierassembly member 646 is continuously connected with the planet carrierassembly member 636 and the output shaft 19 through the interconnectingmember 678. The sun gear member 642 is continuously connected with thesun gear member 652 through the interconnecting member 679.

The ring gear member 624 is selectively connectable with thetransmission housing 680 through the braking synchronizer 664. The ringgear member 634 is selectively connectable with the transmission housing680 through the braking synchronizer 665. The planet carrier assemblymember 626 is selectively connectable with the transmission housing 680through the braking synchronizer 666. The ring gear member 624 isselectively connectable with the input shaft 17 through the input clutch662 and the rotating synchronizer 667. The sun gear member 632 isselectively connectable with the input shaft 17 through the input clutch662 and the rotating synchronizer 668. The ring gear member 654 isselectively connectable with the transmission housing 680 through thebraking synchronizer 669. The planet carrier assembly member 656 isselectively connectable with the transmission housing 680 through thebraking synchronizer 670. The planet carrier assembly member 646 isselectively connectable with the ring gear member 654 through therotating synchronizer 671. The planet carrier assembly member 646 isselectively connectable with the planet carrier assembly member 656through the rotating synchronizer 672.

As shown in FIG. 7b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio. The ratio values given are byway example and are established utilizing the ring gear/sun gear toothratios given in FIG. 7b. For example, the R1/S2 value is the tooth ratioof the planetary gear set 620; the R2/S2 value is the tooth ratio of theplanetary gear set 630; the R3/S3 value is the tooth ratio of theplanetary gear set 640; and the R4/S4 value is the tooth ratio of theplanetary gear set 650. The ratio steps between adjacent forward ratiosand the reverse to first ratio are also given in FIG. 7b.

Those skilled in the art will, upon reviewing the truth table of FIG.7b, recognize that the numerical values of the reverse, third and fifthforward speed ratios are determined utilizing the ring gear/sun geartooth ratios of the planetary gear sets 620, 630. The numerical value ofthe first forward speed ratio is determined utilizing the ring gear/sungear tooth ratio of the planetary gear set 630. The numerical value ofthe second forward speed ratio is determined utilizing the ring gear/sungear tooth ratios of the planetary gear sets 640, 650. The numericalvalue of the fourth forward speed ratio is 1. The numerical value of thesixth forward speed ratio is determined utilizing the ring gear/sun geartooth ratio of the planetary gear set 640.

A powertrain 710, shown in FIG. 8a, has the conventional engine 12, aplanetary transmission 714, and the conventional final drive mechanism16. The engine 12 is continuously connected with the input shaft 17. Theplanetary transmission 714 is drivingly connected with the final drivemechanism 16 through the output shaft 19. The planetary transmission 714includes a planetary gear arrangement 718 that has a first planetarygear set 720, a second planetary gear set 730, a third planetary gearset 740, and a fourth planetary gear set 750.

The planetary gear set 720 includes a sun gear member 722, a ring gearmember 724, and a planet carrier assembly member 726. The planet carrierassembly member 726 includes a plurality of intermeshing pinion gears727, 728 rotatably mounted on a carrier member 729 and disposed inmeshing relationship with the ring gear member 724 and the sun gearmember 722, respectively.

The planetary gear set 730 includes a sun gear member 732, a ring gearmember 734, and a planet carrier assembly member 736. The planet carrierassembly member 736 includes a plurality of pinion gears 737 rotatablymounted on a carrier member 739 and disposed in meshing relationshipwith both the sun gear member 732 and the ring gear member 734.

The planetary gear set 740 includes a sun gear member 742, a ring gearmember 744, and a planet carrier assembly member 746. The planet carrierassembly member 746 includes a plurality of pinion gears 747 rotatablymounted on a carrier member 749 and disposed in meshing relationshipwith both the sun gear member 742 and the ring gear member 744.

The planetary gear set 750 includes a sun gear member 752, a ring gearmember 754, and a planet carrier assembly member 756. The planet carrierassembly member 756 includes a plurality of intermeshing pinion gears757, 758 rotatably mounted on a carrier member 759 and disposed inmeshing relationship with the ring gear member 754 and the sun gearmember 752, respectively.

As a result of the dual clutch arrangement of the invention, the fourplanetary gear sets 720, 730, 740 and 750 are divided into first andsecond transmission subsets 760, 761 which are alternatively engaged toprovide odd number and even number speed ranges, respectively.Transmission subset 760 includes planetary gear sets 720 and 730, andtransmission subset 761 includes planetary gear sets 740 and 750. Theoutput shaft 19 is continuously connected with members of both subsets760 and 761.

As mentioned above, the first and second input clutches 762, 763 arealternatively engaged for transmitting power from the input shaft 17 totransmission subset 760 or transmission subset 761. The first and secondinput clutches 762, 763 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 760, 761 prior to engagingthe respective input clutches 762, 763. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms764, 765, 766, 767, 768, 769, 770, 771 and 772. The torque transmittingmechanisms 764, 765, 769 and 770 comprise braking synchronizers, and thetorque transmitting mechanisms 766, 767, 768, 771 and 772 compriserotating synchronizers.

Accordingly, the input shaft 17 is alternately connected with the firstand second transmission subsets 760, 761 (i.e. through the clutch 762 tosynchronizers 766, 767, 768 and through the clutch 763 to the ring gearmember 744). The ring gear member 724 is continuously connected with theplanet carrier assembly member 736 through the interconnecting member774. The planet carrier assembly member 726 is continuously connectedwith the sun gear member 732 through the interconnecting member 776. Theplanet carrier assembly member 746 is continuously connected with thering gear member 734 and the output shaft 19 through the interconnectingmember 778. The sun gear member 742 is continuously connected with theplanet carrier assembly member 756 through the input clutch 779.

The planet carrier assembly member 726 is selectively connectable withthe transmission housing 780 through the braking synchronizer 764. Thering gear member 724 is selectively connectable with the transmissionhousing 780 through the braking synchronizer 765. The planet carrierassembly member 726 is selectively connectable with the input shaft 17through the input clutch 762 and the rotating synchronizer 766. The sungear member 722 is selectively connectable with the input shaft 17through the input clutch 762 and the rotating synchronizer 767. Theplanet carrier assembly member 736 is selectively connectable with theinput shaft 17 through the input clutch 762 and the rotatingsynchronizer 768. The ring gear member 754 is selectively connectablewith the transmission housing 780 through the braking synchronizer 769.The sun gear member 752 is selectively connectable with the transmissionhousing 780 through the braking synchronizer 770. The planet carrierassembly member 746 is selectively connectable with the ring gear member754 through the rotating synchronizer 771. The planet carrier assemblymember 746 is selectively connectable with the sun gear member 752through the rotating synchronizer 772.

As shown in FIG. 8b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio. Also given in the truth table isa set of numerical values that are attainable with the present inventionutilizing the ring gear/sun gear tooth ratios given in FIG. 8b. TheR1/S1 value is the tooth ratio of the planetary gear set 720; the R2/S2value is the tooth ratio of the planetary gear set 730; the R3/S3 valueis the tooth ratio of the planetary gear set 740; and the R4/S4 value isthe tooth ratio of the planetary gear set 750.

FIG. 8b also provides a chart of the ratio steps between adjacentforward ratios and between the reverse and first forward ratio. Forexample, the ratio step between the first and second forward ratios is1.55.

Those skilled in the art will recognize that the numerical values of thereverse and fifth forward speed ratios are determined utilizing the ringgear/sun gear tooth ratio of the planetary gear set 730. The numericalvalues of the first and third forward speed ratios are determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets720, 730. The numerical values of the second and sixth forward speedratios are determined utilizing the ring gear/sun gear tooth ratios ofthe planetary gear sets 740, 750. The numerical value of the fourthforward speed ratio is 1.

A powertrain 810, shown in FIG. 9a, has the conventional engine 12, aplanetary transmission 814, and the final drive mechanism 16. The engine12 is continuously connected with the input shaft 17. The planetarytransmission 814 is drivingly connected with final drive mechanism 16through output shaft 19. The planetary transmission 814 includes aplanetary gear arrangement 818 that has a first planetary gear set 820,a second planetary gear set 830, a third planetary gear set 840, andfourth planetary gear set 850.

The planetary gear set 820 includes a sun gear member 822, a ring gearmember 824, and a planet carrier assembly member 826. The planet carrierassembly member 826 includes a plurality of pinion gears 827 rotatablymounted on a carrier member 829 and disposed in meshing relationshipwith both the sun gear member 822 and the ring gear member 824.

The planetary gear set 830 includes a sun gear member 832, a ring gearmember 834, and a planet carrier assembly member 836. The planet carrierassembly member 836 includes a plurality of intermeshing pinion gears837, 838 rotatably mounted on a carrier member 839 and disposed inmeshing relationship with the ring gear member 834 and the sun gearmember 832, respectively.

The planetary gear set 840 includes a sun gear member 842, a ring gearmember 844, and a planet carrier assembly member 846. The planet carrierassembly member 846 includes a plurality of pinion gears 847 rotatablymounted on a carrier member 849 and disposed in meshing relationshipwith both the sun gear member 842 and the ring gear member 844.

The planetary gear set 850 includes a sun gear member 852, a ring gearmember 854, and a planet carrier assembly member 856. The planet carrierassembly member 856 includes a plurality of intermeshing pinion gears857, 858 rotatably mounted on a carrier member 859 and disposed inmeshing relationship with the ring gear member 854 and the sun gearmember 852, respectively.

As a result of the dual clutch arrangement of the invention, the fourplanetary gear sets 820, 830, 840 and 850 are divided into first andsecond transmission subsets 860, 861 which are alternatively engaged toprovide odd number and even number speed ranges, respectively.Transmission subset 860 includes planetary gear sets 820 and 830, andtransmission subset 861 includes planetary gear sets 840 and 850. Theoutput shaft 19 is continuously connected with members of both subsets860 and 861.

As mentioned above, the first and second input clutches 862, 863 arealternatively engaged for transmitting power from the input shaft 17 totransmission subset 860 or transmission subset 861. The first and secondinput clutches 862, 863 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratioselection is preselected within the transmission subsets 860, 861 priorto engaging the respective input clutches 862, 863. The preselection isachieved by means of electronically controlled synchronizers. As shown,the planetary gear arrangement includes nine torque transmittingmechanisms 864, 865, 866, 867, 868, 869, 870, 871 and 872. The torquetransmitting mechanisms 864, 865, 866, 869 and 870 comprise brakingsynchronizers, and the torque transmitting mechanisms 867, 868, 871 and872 comprise rotating synchronizers.

Accordingly, the input shaft 17 is alternately connected with the firstand second transmission subsets 860, 861 (i.e. through the clutch 862 tosynchronizers 867, 868 and through the clutch 863 to the sun gear member842). The sun gear member 822 is continuously connected with the planetcarrier assembly member 836 through the interconnecting member 874. Thering gear member 824 is continuously connected with the sun gear member832 through the interconnecting member 876. The planet carrier assemblymember 846 is continuously connected with the planet carrier assemblymember 826 and the output shaft 19 through the interconnecting member878. The ring gear member 844 is continuously connected with the planetcarrier assembly member 856 through the interconnecting member 879.

The ring gear member 834 is selectively connectable with thetransmission housing 880 through the braking synchronizer 864. The sungear member 832 is selectively connectable with the transmission housing880 through the braking synchronizer 865. The planet carrier assemblymember 836 is selectively connectable with the transmission housing 880through the braking synchronizer 866. The ring gear member 834 isselectively connectable with the input shaft 17 through the input clutch862 and the rotating synchronizer 867. The sun gear member 822 isselectively connectable with the input shaft 17 through the input clutch862 and the rotating synchronizer 868. The sun gear member 852 isselectively connectable with the transmission housing 880 through thebraking synchronizer 869. The ring gear member 854 is selectivelyconnectable with the transmission housing 880 through the brakingsynchronizer 870. The planet carrier assembly member 846 is selectivelyconnectable with the sun gear member 852 through the rotatingsynchronizer 871. The planet carrier assembly member 846 is selectivelyconnectable with the ring gear member 854 through the rotatingsynchronizer 872.

As shown in FIG. 9b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio. A sample of numerical values forthe individual ratios is also given in the truth table of FIG. 9b. Thesenumerical values have been calculated using the ring gear/sun gear toothratios also given by way of example in FIG. 9b. The R1/S1 value is thetooth ratio of the planetary gear set 820; the R2/S2 value is the toothratio of planetary gear set 830; the R3/S3 value is the tooth ratio ofthe planetary gear set 840; and the R4/S4 value is the tooth ratio ofthe planetary gear set 850. FIG. 9b also describes the ratio stepsbetween adjacent forward ratios and between the reverse and firstforward ratio. For example, the ratio step between the first and secondforward ratios is 1.60.

Those skilled in the art will recognize that the numerical values of thereverse, fourth and sixth forward speed ratios are determined utilizingthe ring gear/sun gear tooth ratios of the planetary gear sets 820, 830.The numerical value of the first forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets840, 850. The numerical value of the second forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratio of the planetarygear set 830. The numerical value of the third forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratio of the planetarygear set 840. The numerical value of the fifth forward speed ratio is 1.

Referring to FIG. 10a, a powertrain 910 is shown having a conventionalengine 12, a planetary transmission 914, and a conventional final drivemechanism 16. The planetary transmission 914 includes an input shaft 17connected with the engine 12, a planetary gear arrangement 918, and anoutput shaft 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 918 includes four planetary gear sets920, 930, 940 and 950.

The planetary gear set 920 includes a sun gear member 922, a ring gearmember 924, and a planet carrier assembly member 926. The planet carrierassembly member 926 includes a plurality of intermeshing pinion gears927, 928 rotatably mounted on a carrier member 929 and disposed inmeshing relationship with the ring gear member 924 and the sun gearmember 922, respectively.

The planetary gear set 930 includes a sun gear member 932, a ring gearmember 934, and a planet carrier assembly member 936. The planet carrierassembly member 936 includes a plurality of pinion gears 937 rotatablymounted on a carrier member 939 and disposed in meshing relationshipwith both the sun gear member 932 and the ring gear member 934.

The planetary gear set 940 includes a sun gear member 942, a ring gearmember 944, and a planet carrier assembly member 946. The planet carrierassembly member 946 includes a plurality of pinion gears 947 rotatablymounted on a carrier member 949 and disposed in meshing relationshipwith both the sun gear member 942 and the ring gear member 944.

The planetary gear set 950 includes a sun gear member 952, a ring gearmember 954, and a planet carrier assembly member 956. The planet carrierassembly member 956 includes a plurality of intermeshing pinion gears957, 958 rotatably mounted on a carrier member 959 and disposed inmeshing relationship with the ring gear member 954 and the sun gearmember 952, respectively.

As a result of the dual clutch arrangement of the invention, the fourplanetary gear sets 920, 930, 940 and 950 are divided into first andsecond transmission subsets 960, 961 which are alternatively engaged toprovide odd number and even number speed ranges, respectively.Transmission subset 960 includes planetary gear sets 920 and 930, andtransmission subset 961 includes planetary gear sets 940 and 950. Theoutput shaft 19 is continuously connected with members of both subsets960 and 961.

As mentioned above, the first and second input clutches 962, 963 arealternatively engaged for transmitting power from the input shaft 17 totransmission subset 960 or transmission subset 961. The first and secondinput clutches 962, 963 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 960, 961 prior to engagingthe respective input clutches 962, 963. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms964, 965, 966, 967, 968, 969, 970, 971 and 972. The torque transmittingmechanisms 964, 965, 966, 969 and 970 comprise braking synchronizers,and the torque transmitting mechanisms 967, 968, 971 and 972 compriserotating synchronizers.

Accordingly, the input shaft 17 is alternately connected with the firstand second transmission subsets 960, 961 (i.e. through the clutch 962 tosynchronizers 967, 968 and through the clutch 963 to the ring gearmember 944). The sun gear member 922 is continuously connected with thering gear member 934 through the interconnecting member 974. The planetcarrier assembly member 926 is continuously connected with the sun gearmember 932 through the interconnecting member 976. The planet carrierassembly member 946 is continuously connected with the planet carrierassembly member 936 and the output shaft 19 through the interconnectingmember 978. The sun gear member 942 is continuously connected with theplanet carrier assembly member 956 through the interconnecting member979.

The ring gear member 924 is selectively connectable with thetransmission housing 980 through the braking synchronizer 964. The ringgear member 934 is selectively connectable with the transmission housing980 through the braking synchronizer 965. The planet carrier assemblymember 926 is selectively connectable with the transmission housing 980through the braking synchronizer 966. The ring gear member 924 isselectively connectable with the input shaft 17 through the input clutch962 and the rotating synchronizer 967. The sun gear member 932 isselectively connectable with the input shaft 17 through the input clutch962 and the rotating synchronizer 968. The ring gear member 954 isselectively connectable with the transmission housing 980 through thebraking synchronizer 969. The sun gear member 952 is selectivelyconnectable with the transmission housing 980 through the brakingsynchronizer 970. The planet carrier assembly member 946 is selectivelyconnectable with the ring gear member 954 through the rotatingsynchronizer 971. The planet carrier assembly member 946 is selectivelyconnectable with the sun gear member 952 through the rotatingsynchronizer 972.

As shown in FIG. 10b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio. The truth table also provides aset of examples for the numerical values for each of the reverse andforward speed ratios. These numerical values have been determinedutilizing the ring gear/sun gear tooth ratios given in FIG. 10b. TheR1/S1 value is the tooth ratio of the planetary gear set 920; the R2/S2value is the tooth ratio of the planetary gear set 930; the R3/S3 valueis the tooth ratio of the planetary gear set 940; and the R4/S4 value isthe tooth ratio of the planetary gear set 950.

Those skilled in the art, upon reviewing the engagement combinations,will recognize that the numerical values of the reverse, third and fifthforward speed ratios are determined utilizing the ring gear/sun geartooth ratios of the planetary gear sets 920, 930. The numerical value ofthe first forward speed ratio is determined utilizing the ring gear/sungear tooth ratio of the planetary gear set 930. The numerical values ofthe second and sixth forward speed ratios are determined utilizing thering gear/sun gear tooth ratios of the planetary gear sets 940, 950. Thenumerical value of the fourth forward speed ratio is 1.

Referring to FIG. 11a, a powertrain 1010 is shown having a conventionalengine 12, a planetary transmission 1014, and a conventional final drivemechanism 16. The planetary transmission 1014 includes an input shaft 17connected with the engine 12, a planetary gear arrangement 1018, and anoutput shaft 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 1018 includes four planetary gearsets 1020, 1030, 1040 and 1050.

The planetary gear set 1020 includes a sun gear member 1022, a ring gearmember 1024, and a planet carrier assembly member 1026. The planetcarrier assembly member 1026 includes a plurality of intermeshing piniongears 1027, 1028 rotatably mounted on a carrier member 1029 and disposedin meshing relationship with the ring gear member 1024 and the sun gearmember 1022, respectively.

The planetary gear set 1030 includes a sun gear member 1032, a ring gearmember 1034, and a planet carrier assembly member 1036. The planetcarrier assembly member 1036 includes a plurality of pinion gears 1037rotatably mounted on a carrier member 1039 and disposed in meshingrelationship with both the sun gear member 1032 and the ring gear member1034.

The planetary gear set 1040 includes a sun gear member 1042, a ring gearmember 1044, and a planet carrier assembly member 1046. The planetcarrier assembly member 1046 includes a plurality of pinion gears 1047rotatably mounted on a carrier member 1049 and disposed in meshingrelationship with both the sun gear member 1042 and the ring gear member1044.

The planetary gear set 1050 includes a sun gear member 1052, a ring gearmember 1054, and a planet carrier assembly member 1056. The planetcarrier assembly member 1056 includes a plurality of intermeshing piniongears 1057, 1058 rotatably mounted on a carrier member 1059 and disposedin meshing relationship with the ring gear member 1054 and the sun gearmember 1052, respectively.

As a result of the dual clutch arrangement of the invention, the fourplanetary gear sets 1020, 1030, 1040 and 1050 are divided into first andsecond transmission subsets 1060, 1061 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 1060 includes planetary gear sets 1020 and 1030, andtransmission subset 1061 includes planetary gear sets 1040 and 1050. Theoutput shaft 19 is continuously connected with members of both subsets1060 and 1061.

As mentioned above, the first and second input clutches 1062, 1063 arealternatively engaged for transmitting power from the input shaft 17 totransmission subset 1060 or transmission subset 1061. The first andsecond input clutches 1062, 1063 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 1060, 1061 prior to engagingthe respective input clutches 1062, 1063. The preselection is achievedby means of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms1064, 1065, 1066, 1067, 1068, 1069, 1070, 1071 and 1072. The torquetransmitting mechanisms 1064, 1065, 1066, 1069 and 1070 comprise brakingsynchronizers, and the torque transmitting mechanisms 1067, 1068, 1071and 1072 comprise rotating synchronizers.

Accordingly, the input shaft 17 is alternately connected with the firstand second transmission subsets 1060, 1061 (i.e. through the clutch 1062to synchronizers 1067, 1068 and through the clutch 1063 to the sun gearmember 1042). The sun gear member 1022 is continuously connected withthe ring gear member 1034 through the interconnecting member 1074. Theplanet carrier assembly member 1026 is continuously connected with thesun gear member 1032 through the interconnecting member 1076. The planetcarrier assembly member 1046 is continuously connected with the planetcarrier assembly member 1036 and the output shaft 19 through theinterconnecting member 1078. The ring gear member 1044 is continuouslyconnected with the ring gear member 1054 through the interconnectingmember 1079.

The ring gear member 1024 is selectively connectable with thetransmission housing 1080 through the braking synchronizer 1064. Thering gear member 1034 is selectively connectable with the transmissionhousing 1080 through the braking synchronizer 1065. The planet carrierassembly member 1026 is selectively connectable with the transmissionhousing 1080 through the braking synchronizer 1066. The ring gear member1024 is selectively connectable with the input shaft 17 through theinput clutch 1062 and the rotating synchronizer 1067. The sun gearmember 1032 is selectively connectable with the input shaft 17 throughthe input clutch 1062 and the rotating synchronizer 1068. The planetcarrier assembly member 1056 is selectively connectable with thetransmission housing 1080 through the braking synchronizer 1069. The sungear member 1052 is selectively connectable with the transmissionhousing 1080 through the braking synchronizer 1070. The planet carrierassembly member 1046 is selectively connectable with the planet carrierassembly member 1056 through the rotating synchronizer 1071. The planetcarrier assembly member 1046 is selectively connectable with the sungear member 1052 through the rotating synchronizer 1072.

As shown in FIG. 11b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio. The truth table also provides aset of examples for the numerical values for each of the reverse andforward speed ratios. These numerical values have been determinedutilizing the ring gear/sun gear tooth ratios given in FIG. 11b. TheR1/S1 value is the tooth ratio of the planetary gear set 1020; the R2/S2value is the tooth ratio of the planetary gear set 1030; the R3/S3 valueis the tooth ratio of the planetary gear set 1040; and the R4/S4 valueis the tooth ratio of the planetary gear set 1050.

Those skilled in the art, upon reviewing the engagement combinations,will recognize that the numerical values of the reverse, fourth andsixth forward speed ratios are determined utilizing the ring gear/sungear tooth ratios of the planetary gear sets 1020, 1030. The numericalvalue of the first forward speed ratio is determined utilizing the ringgear/sun gear tooth ratio of the planetary gear set 1040. The numericalvalue of the second forward speed ratio is determined utilizing the ringgear/sun gear tooth ratio of the planetary gear set 1030. The numericalvalue of the third forward speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 1040, 1050. Thenumerical value of the fifth forward speed ratio is 1.

FIG. 12a shows a powertrain 1110 having a conventional engine 12, aplanetary transmission 1114, and a conventional final drive mechanism16. The planetary transmission 1114 includes an input shaft 17 connectedwith the engine 12, a planetary gear arrangement 1118, and an outputshaft 19 connected with the final drive mechanism 16. The planetary geararrangement 118 includes four planetary gear sets 1120, 1130, 1140 and1150.

The planetary gear set 1120 includes a sun gear member 1122, a ring gearmember 1124, and a planet carrier assembly member 1126. The planetcarrier assembly member 1126 includes a plurality of pinion gears 1127rotatably mounted on a carrier member 1129 and disposed in meshingrelationship with both the sun gear member 1122 and the ring gear member1124.

The planetary gear set 1130 includes a sun gear member 1132, a ring gearmember 1134, and a planet carrier assembly member 1136. The planetcarrier assembly member 1136 includes a plurality of intermeshing piniongears 1137, 1138 rotatably mounted on a carrier member 1139 and disposedin meshing relationship with the ring gear member 1134 and the sun gearmember 1132, respectively.

The planetary gear set 1140 includes a sun gear member 1142, a ring gearmember 1144, and a planet carrier assembly member 1146. The planetcarrier assembly member 1146 includes a plurality of pinion gears 1147rotatably mounted on a carrier member 1149 and disposed in meshingrelationship with both the sun gear member 1142 and the ring gear member1144.

The planetary gear set 1150 includes a sun gear member 1152, a ring gearmember 1154, and a planet carrier assembly member 1156. The planetcarrier assembly member 1156 includes a plurality of intermeshing piniongears 1157, 1158 rotatably mounted on a carrier member 1159 and disposedin meshing relationship with the ring gear member 1154 and the sun gearmember 1152, respectively.

As a result of the dual clutch arrangement of the invention, the fourplanetary gear sets 1120, 1130, 1140 and 1150 are divided into first andsecond transmission subsets 1160, 1161 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 1160 includes planetary gear sets 1120 and 1130, andtransmission subset 1161 includes planetary gear sets 1140 and 1150. Theoutput shaft 19 is continuously connected with members of both subsets1160 and 1161.

As mentioned above, the first and second input clutches 1162, 1163 arealternatively engaged for transmitting power from the input shaft 17 totransmission subset 1160 or transmission subset 1161. The first andsecond input clutches 1162, 1163 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 1160, 1161 prior to engagingthe respective input clutches 1162, 1163. The preselection is achievedby means of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms1164, 1165, 1166, 1167, 1168, 1169, 1170, 1171 and 1172. The torquetransmitting mechanisms 1164, 1165, 1169 and 1170 comprise brakingsynchronizers, and the torque transmitting mechanisms 1166, 1167, 1168,1171 and 1172 comprise rotating synchronizers.

Accordingly, the input shaft 17 is alternately connected with the firstand second transmission subsets 1160, 1161 (i.e. through the clutch 1162to synchronizers 1166, 1167, 1168 and through the clutch 1163 to thering gear member 1144). The planet carrier assembly member 1126 iscontinuously connected with the planet carrier assembly member 1136through the interconnecting member 1174. The ring gear member 1124 iscontinuously connected with the sun gear member 1132 through theinterconnecting member 1176. The planet carrier assembly member 1146 iscontinuously connected with the ring gear member 1134 and the outputshaft 19 through the interconnecting member 1178. The sun gear member1142 is continuously connected with the planet carrier assembly member1156 through the interconnecting member 1179.

The sun gear member 1122 is selectively connectable with thetransmission housing 1180 through the braking synchronizer 1164. Theplanet carrier assembly member 1136 is selectively connectable with thetransmission housing 1180 through the braking synchronizer 1165. The sungear member 1122 is selectively connectable with the input shaft 17through the input clutch 1162 and the rotating synchronizer 1166. Thering gear member 1124 is selectively connectable with the input shaft 17through the input clutch 1162 and the rotating synchronizer 1167. Theplanet carrier assembly member 1136 is selectively connectable with theinput shaft 17 through the input clutch 1162 and the rotatingsynchronizer 1168. The ring gear member 1154 is selectively connectablewith the transmission housing 1180 through the braking synchronizer1169. The sun gear member 1152 is selectively connectable with thetransmission housing 1180 through the braking synchronizer 1170. Theplanet carrier assembly member 1146 is selectively connectable with thering gear member 1154 through the rotating synchronizer 1171. The planetcarrier assembly member 1146 is selectively connectable with the sungear member 1152 through the rotating synchronizer 1172.

As shown in FIG. 12b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio.

Those skilled in the art will recognize that the numerical values of thereverse, third and fifth forward speed ratios are determined utilizingthe ring gear/sun gear tooth ratios of the planetary gear sets 1120,1130. The numerical value of the first forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratio of the planetary gear set1130. The numerical values of the second and sixth forward speed ratiosare determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 1140, 1150. The numerical value of the fourthforward speed ratio is 1.

As set forth above, the truth table of FIG. 12b describes the engagementsequence of the torque transmitting mechanisms utilized to provide areverse drive ratio and six forward speed ratios. The truth table alsoprovides an example of the ratios that can be attained with the familymembers shown in FIG. 12a utilizing the sample tooth ratios given inFIG. 12b. The R1/S1 value is the tooth ratio of the planetary gear set1120; the R2/S2 value is the tooth ratio of the planetary gear set 1130;the R3/S3 value is the tooth ratio of the planetary gear set 1140; andthe R4/S4 value is the tooth ratio of the planetary gear set 1150. Alsoshown in FIG. 12b are the ratio steps between single step ratios in theforward direction as well as the reverse to first ratio step. Forexample, the first to second step ratio is 1.57.

Turning the FIG. 13a, a powertrain 1210 having a conventional engine 12,a planetary transmission 1214, and conventional final drive mechanism 16is shown.

The planetary transmission 1214 includes an input shaft 17 continuouslyconnected with the engine 12, a planetary gear arrangement 1218, and anoutput shaft 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 1218 includes four planetary gearsets 1220, 1230, 1240 and 1250.

The planetary gear set 1220 includes a sun gear member 1222, a ring gearmember 1224, and a planet carrier assembly member 1226. The planetcarrier assembly member 1226 includes a plurality of pinion gears 1227rotatably mounted on a carrier member 1229 and disposed in meshingrelationship with both the sun gear member 1222 and the ring gear member1224.

The planetary gear set 1230 includes a sun gear member 1232, a ring gearmember 1234, and a planet carrier assembly member 1236. The planetcarrier assembly member 1236 includes a plurality of intermeshing piniongears 1237, 1238 rotatably mounted on a carrier member 1239 and disposedin meshing relationship with the ring gear member 1234 and the sun gearmember 1232, respectively.

The planetary gear set 1240 includes a sun gear member 1242, a ring gearmember 1244, and a planet carrier assembly member 1246. The planetcarrier assembly member 1246 includes a plurality of pinion gears 1247rotatably mounted on a carrier member 1249 and disposed in meshingrelationship with both the sun gear member 1242 and the ring gear member1244.

The planetary gear set 1250 includes a sun gear member 1252, a ring gearmember 1254, and a planet carrier assembly member 1256. The planetcarrier assembly member 1256 includes a plurality of intermeshing piniongears 1257, 1258 rotatably mounted on a carrier member 1259 and disposedin meshing relationship with the ring gear member 1254 and the sun gearmember 1252, respectively.

As a result of the dual clutch arrangement of the invention, the fourplanetary gear sets 1220, 1230, 1240 and 1250 are divided into first andsecond transmission subsets 1260, 1261 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 1260 includes planetary gear sets 1220 and 1230, andtransmission subset 1261 includes planetary gear sets 1240 and 1250. Theoutput shaft 19 is continuously connected with members of both subsets1260 and 1261.

As mentioned above, the first and second input clutches 1262, 1263 arealternatively engaged for transmitting power from the input shaft 17 totransmission subset 1260 or transmission subset 1261. The first andsecond input clutches 1262, 1263 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 1260, 261 prior to engagingthe respective input clutches 1262, 1263. The preselection is achievedby means of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms1264, 1265, 1266, 1267, 1268, 1269, 1270, 1271 and 1272. The torquetransmitting mechanisms 1264, 1265, 1269 and 1270 comprise brakingsynchronizers, and the torque transmitting mechanisms 1266, 1267, 1268,1271 and 1272 comprise rotating synchronizers.

Accordingly, the input shaft 17 is alternately connected with the firstand second transmission subsets 1260, 1261 (i.e. through the clutch 1262to synchronizers 1266, 1267, 1268 and through the clutch 1263 to thering gear member 1244). The planet carrier assembly member 1226 iscontinuously connected with the planet carrier assembly member 1236through the interconnecting member 1274. The ring gear member 1224 iscontinuously connected with the sun gear member 1232 through theinterconnecting member 1276. The planet carrier assembly member 1246 iscontinuously connected with the ring gear member 1234 and the outputshaft 19 through the interconnecting member 1278. The sun gear member1242 is continuously connected with the sun gear member 1252 through theinterconnecting member 1279.

The sun gear member 1222 is selectively connectable with thetransmission housing 1280 through the braking synchronizer 1264. Theplanet carrier assembly member 1236 is selectively connectable with thetransmission housing 1280 through the braking synchronizer 1265. The sungear member 1222 is selectively connectable with the input shaft 17through the input clutch 1262 and the rotating synchronizer 1266. Thering gear member 1224 is selectively connectable with the input shaft 17through the input clutch 1262 and the rotating synchronizer 1267. Theplanet carrier assembly member 1236 is selectively connectable with theinput shaft 17 through the input clutch 1262 and the rotatingsynchronizer 1268. The ring gear member 1254 is selectively connectablewith the transmission housing 1280 through the braking synchronizer1269. The planet carrier assembly member 1256 is selectively connectablewith the transmission housing 1280 through the braking synchronizer1270. The planet carrier assembly member 1246 is selectively connectablewith the ring gear member 1254 through the rotating synchronizer 1271.The planet carrier assembly member 1246 is selectively connectable withthe planet carrier assembly member 1256 through the rotatingsynchronizer 1272.

As shown in FIG. 13b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio.

Those skilled in the art will recognize that the numerical values of thereverse, third and fifth forward speed ratios are determined utilizingthe ring gear/sun gear tooth ratios of the planetary gear sets 1220,1230. The numerical value of the first forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratio of the planetary gear set1230. The numerical values of the second and sixth forward speed ratiosare determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 1240, 1250. The numerical value of the fourthforward speed ratio is 1.

As previously set forth, the truth table of FIG. 13b describes thecombinations of engagements utilized for six forward speed ratios andone reverse speed ratio. The truth table also provides an example ofspeed ratios that are available with the family member described above.These examples of speed ratios are determined the tooth ratios given inFIG. 13b. The R1/S1 value is the tooth ratio of the planetary gear set1220; the R2/S2 value is the tooth ratio of the planetary gear set 1230;the R3/S3 value is the tooth ratio of the planetary gear set 1240; andthe R4/S4 value is the tooth ratio of the planetary gear set 1250. Alsodepicted in FIG. 13b is a chart representing the ratio steps betweenadjacent forward speed ratios and the reverse speed ratio. For example,the first to second ratio interchange has a step of 1.49.

A powertrain 1310, shown in FIG. 14a, includes the engine 12, aplanetary transmission 1314, and the final drive mechanism 16. Theplanetary transmission 1314 includes an input shaft 17 continuouslyconnected with the engine 12, a planetary gear arrangement 1318, and anoutput shaft 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 1318 includes four planetary gearsets 1320, 1330, 1340 and 1350.

The planetary gear set 1320 includes a sun gear member 1322, a ring gearmember 1324, and a planet carrier assembly member 1326. The planetcarrier assembly member 1326 includes a plurality of intermeshing piniongears 1327, 1328 rotatably mounted on a carrier member 1329 and disposedin meshing relationship with the ring gear member 1324 and the sun gearmember 1322, respectively.

The planetary gear set 1330 includes a sun gear member 1332, a ring gearmember 1334, and a planet carrier assembly member 1336. The planetcarrier assembly member 1336 includes a plurality of pinion gears 1337rotatably mounted on a carrier member 1339 and disposed in meshingrelationship with both the sun gear member 1332 and the ring gear member1334.

The planetary gear set 1340 includes a sun gear member 1342, a ring gearmember 1344, and a planet carrier assembly member 1346. The planetcarrier assembly member 1346 includes a plurality of intermeshing piniongears 1347, 1348 rotatably mounted on a carrier member 1349 and disposedin meshing relationship with the ring gear member 1344 and the sun gearmember 1342, respectively.

The planetary gear set 1350 includes a sun gear member 1352, a ring gearmember 1354, and a planet carrier assembly member 1356. The planetcarrier assembly member 1356 includes a plurality of pinion gears 1357rotatably mounted on a carrier member 1359 and disposed in meshingrelationship with both the sun gear member 1352 and the ring gear member1354.

As a result of the dual clutch arrangement of the invention, the fourplanetary gear sets 1320, 1330, 1340 and 1350 are divided into first andsecond transmission subsets 1360, 1361 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 1360 includes planetary gear sets 1320 and 1330, andtransmission subset 1361 includes planetary gear sets 1340 and 1350. Theoutput shaft 19 is continuously connected with members of both subsets1360 and 1361.

As mentioned above, the first and second input clutches 1362, 1363 arealternatively engaged for transmitting power from the input shaft 17 totransmission subset 1360 or transmission subset 1361. The first andsecond input clutches 1362, 1363 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 1360, 1361 prior to engagingthe respective input clutches 1362, 1363. The preselection is achievedby means of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms1364, 1365, 1366, 1367, 1368, 1369, 1370, 1371 and 1372. The torquetransmitting mechanisms 1364, 1365, 1369 and 1370 comprise brakingsynchronizers, and the torque transmitting mechanisms 1366, 1367, 1368,1371 and 1372 comprise rotating synchronizers.

Accordingly, the input shaft 17 is alternately connected with the firstand second transmission subsets 1360, 1361 (i.e. through the clutch 1362to synchronizers 1366, 1367, 1368 and through the clutch 1363 to thering gear member 1344). The ring gear member 1324 is continuouslyconnected with the planet carrier assembly member 1336 through theinterconnecting member 1374. The planet carrier assembly member 1326 iscontinuously connected with the sun gear member 1332 through theinterconnecting member 1376. The planet carrier assembly member 1346 iscontinuously connected with the ring gear member 1334 and the outputshaft 19 through the interconnecting member 1378. The sun gear member1342 is continuously connected with the sun gear member 1352 through theinterconnecting member 1379.

The planet carrier assembly member 1326 is selectively connectable withthe transmission housing 1380 through the braking synchronizer 1364. Thering gear member 1324 is selectively connectable with the transmissionhousing 1380 through the braking synchronizer 1365. The planet carrierassembly member 1326 is selectively connectable with the input shaft 17through the input clutch 1362 and the rotating synchronizer 1366. Thesun gear member 1322 is selectively connectable with the input shaft 17through the input clutch 1362 and the rotating synchronizer 1367. Theplanet carrier assembly member 1336 is selectively connectable with theinput shaft 17 through the input clutch 1362 and the rotatingsynchronizer 1368. The ring gear member 1354 is selectively connectablewith the transmission housing 1380 through the braking synchronizer1369. The planet carrier assembly member 1356 is selectively connectablewith the transmission housing 1380 through the braking synchronizer1370. The planet carrier assembly member 1346 is selectively connectablewith the ring gear member 1354 through the rotating synchronizer 1371.The planet carrier assembly member 1346 is selectively connectable withthe planet carrier assembly member 1356 through the rotatingsynchronizer 1372.

The truth table shown in FIG. 14b describes the engagement combinationand engagement sequence necessary to provide the reverse drive ratio andsix forward speed ratios. A sample of the numerical values for theratios is also provided in the truth table of FIG. 14b. These values aredetermined utilizing the ring gear/sun gear tooth ratios also given inFIG. 14b. The R1/S1 value is the tooth ratio for the planetary gear set1320; the R2/S2 value is the tooth ratio for the planetary gear set1330; the R3/S3 value is the tooth ratio for the planetary gear set1340; and the R4/S4 value is the tooth ratio for the planetary gear set1350. Also given in FIG. 14b is a chart describing the step ratiosbetween the adjacent forward speed ratios and the reverse to firstforward speed ratio. For example, the first to second forward speedratio step is 1.45.

Those skilled in the art will recognize that the numerical values of thereverse and fifth forward speed ratios are determined utilizing the ringgear/sun gear tooth ratio of the planetary gear set 1330. The numericalvalues of the first and third forward speed ratios are determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets1320, 1330. The numerical value of the second forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 1340, 1350. The numerical value of the fourthforward speed ratio is 1. The numerical value of the sixth forward speedratio is determined utilizing the ring gear/sun gear tooth ratio of theplanetary gear set 1340.

A powertrain 1410 shown in FIG. 15a includes a conventional engine 12, aplanetary transmission 1414, and a conventional final drive mechanism16. The planetary transmission 1414 includes an input shaft 17 connectedwith the engine 12, a planetary gear arrangement 1418, and an outputshaft 19 continuously connected with the final drive mechanism 16. Theplanetary gear arrangement 1418 includes four planetary gear sets 1420,1430, 1440 and 1450.

The planetary gear set 1420 includes a sun gear member 1422, a ring gearmember 1424, and a planet carrier assembly member 1426. The planetcarrier assembly member 1426 includes a plurality of intermeshing piniongears 1427, 1428 rotatably mounted on a carrier member 1429 and disposedin meshing relationship with the ring gear member 1424 and the sun gearmember 1422, respectively.

The planetary gear set 1430 includes a sun gear member 1432, a ring gearmember 1434, and a planet carrier assembly member 1436. The planetcarrier assembly member 1436 includes a plurality of pinion gears 1437rotatably mounted on a carrier member 1439 and disposed in meshingrelationship with both the sun gear member 1432 and the ring gear member1434.

The planetary gear set 1440 includes a sun gear member 1442, a ring gearmember 1444, and a planet carrier assembly member 1446. The planetcarrier assembly member 1446 includes a plurality of intermeshing piniongears 1447, 1448 rotatably mounted on a carrier member 1449 and disposedin meshing relationship with the ring gear member 1444 and the sun gearmember 1442, respectively.

The planetary gear set 1450 includes a sun gear member 1452, a ring gearmember 1454, and a planet carrier assembly member 1456. The planetcarrier assembly member 1456 includes a plurality of pinion gears 1457rotatably mounted on a carrier member 1459 and disposed in meshingrelationship with both the sun gear member 1452 and the ring gear member1454.

As a result of the dual clutch arrangement of the invention, the fourplanetary gear sets 1420, 1430, 1440 and 1450 are divided into first andsecond transmission subsets 1460, 1461 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 1460 includes planetary gear sets 1420 and 1430, andtransmission subset 1461 includes planetary gear sets 1440 and 1450. Theoutput shaft 19 is continuously connected with a member of transmissionsubset 1461.

In this family member, which is a derivative of the family member shownin FIG. 14a, rather than having two input clutches and ninesynchronizers, four input clutches and six synchronizers are utilized toachieve reduced content. The first input clutch and first, second andthird synchronizers in FIG. 14a are here operatively replaced by afirst, second and third input clutch 1466, 1467, and 1468 and the secondinput clutch in FIG. 14a remains here as a fourth input clutch 1463. Theinput clutches 1463, 1466, 1467, 1468 are controlled electronically, andthe disengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 1460, 1461 prior to engagingthe respective input clutch 1463, 1466, 1467 or 1468. The preselectionis achieved by means of electronically controlled synchronizers. Asshown, the planetary gear arrangement includes six torque transmittingmechanisms 1464, 1465, 1469, 1470, 1471 and 1472. The torquetransmitting mechanisms 1464, 1465, 1466, 1469 and 1470 comprise brakingsynchronizers, and the torque transmitting mechanisms 1471 and 1472comprise rotating synchronizers.

Accordingly, the input shaft 17 is alternately connected with the firstand second transmission subsets 1460, 1461 (i.e. through the clutch 1466to the planet carrier assembly member 1426, through the clutch 1467 tothe sun gear member 1422, through the clutch 1468 to the planet carrierassembly member 1436 and through the clutch 1463 to the ring gear member1444). The ring gear member 1424 is continuously connected with theplanet carrier assembly member 1436 through the interconnecting member1474. The planet carrier assembly member 1426 is continuously connectedwith the sun gear member 1432 through the interconnecting member 1476.The planet carrier assembly member 1446 is continuously connected withthe ring gear member 1434 and the output shaft 19 through theinterconnecting member 1478. The sun gear member 1442 is continuouslyconnected with the sun gear member 1452 through the interconnectingmember 1479.

The planet carrier assembly member 1426 is selectively connectable withthe transmission housing 1480 through the braking synchronizer 1464. Thering gear member 1424 is selectively connectable with the transmissionhousing 1480 through the braking synchronizer 1465. The planet carrierassembly member 1426 is selectively connectable with the input shaft 17through the rotating synchronizer 1466. The sun gear member 1422 isselectively connectable with the input shaft 17 through the input clutch1467. The planet carrier assembly member 1436 is selectively connectablewith the input shaft 17 through the input clutch 1468. The ring gearmember 1454 is selectively connectable with the transmission housing1480 through the braking synchronizer 1469. The planet carrier assemblymember 1456 is selectively connectable with the transmission housing1480 through the braking synchronizer 1470. The planet carrier assemblymember 1446 is selectively connectable with the ring gear member 1454through the rotating synchronizer 1471. The planet carrier assemblymember 1446 is selectively connectable with the planet carrier assemblymember 1456 through the rotating synchronizer 1472.

As shown in FIG. 15b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of at least two to provide sixforward speed ratios and a reverse speed ratio.

FIG. 15b also provides a chart of the ratio steps between adjacentforward ratios and between the reverse and first ratio. For example, theratio step between the first and second forward ratios is 1.45. Thoseskilled in the art will recognize that the numerical values of thereverse and fifth forward speed ratios are determined utilizing the ringgear/sun gear tooth ratio of the planetary gear set 1430. The numericalvalues of the first and third forward speed ratios are determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets1420, 1430. The numerical value of the second forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 1440, 1450. The numerical value of the fourthforward speed ratio is 1. The numerical value of the sixth forward speedratio is determined utilizing the ring gear/sun gear tooth ratio of theplanetary gear set 1440.

FIGS. 16a and 16 b illustrate a transmission wherein one of the torquetransmitting mechanisms from a previously described configuration iseliminated to realize five forward speed ratios and a reverse speedratio. Specifically, the powertrain 1510, shown in FIG. 16a is identicalto that shown in FIG. 1a, except that the braking synchronizer 66 ofFIG. 1a has been eliminated.

A powertrain 1510, shown in FIG. 16a, includes a conventional engine 12,a powertrain 1514, and a conventional final drive mechanism 16. Thepowertrain 1514 includes an input shaft 17 connected with the engine 12,a planetary gear arrangement 1518, and an output shaft 19 continuouslyconnected with the final drive mechanism 16. The planetary geararrangement 1518 includes four planetary gear sets 1520, 1530, 1540 and1550.

The planetary gear set 1520 includes a sun gear member 1522, a ring gearmember 1524, and a planet carrier assembly member 1526. The planetcarrier assembly member 1526 includes a plurality of intermeshing piniongears 1527, 1528 rotatably mounted on a carrier member 1529 and disposedin meshing relationship with the ring gear member 1524 and the sun gearmember 1522, respectively.

The planetary gear set 1530 includes a sun gear member 1532, a ring gearmember 1534, and a planet carrier assembly member 1536. The planetcarrier assembly member 1536 includes a plurality of pinion gears 1537rotatably mounted on a carrier member 1539 and disposed in meshingrelationship with both the sun gear member 1532 and the ring gear member1534.

The planetary gear set 1540 includes a sun gear member 1542, a ring gearmember 1544, and a planet carrier assembly member 1546. The planetcarrier assembly member 1546 includes a plurality of pinion gears 1547rotatably mounted on a carrier member 1549 and disposed in meshingrelationship with both the sun gear member 1542 and the ring gear member1544.

The planetary gear set 1550 includes a sun gear member 1552, a ring gearmember 1554, and a planet carrier assembly member 1556. The planetcarrier assembly member 1556 includes a plurality of pinion gears 1557rotatably mounted on a carrier member 1559 and disposed in meshingrelationship with both the sun gear member 1552 and the ring gear member1554.

As a result of the dual clutch arrangement of the invention, the fourplanetary gear sets 1520, 1530, 1540 and 1550 are divided into first andsecond transmission subsets 1560, 1561 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 1560 includes planetary gear sets 1520 and 1530, andtransmission subset 1561 includes planetary gear sets 1540 and 1550.

As mentioned above, the first and second input clutches 1562, 1563 arealternatively engaged for transmitting power from the input shaft 17 totransmission subset 1560 or transmission subset 1561. The first andsecond input clutches 1562, 1563 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 1560, 1561 prior to engagingthe respective input clutches 1562, 1563. The preselection is achievedby means of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes eight torque transmitting mechanisms1564, 1565, 1567, 1568, 1569, 1570, 1571 and 1572. The torquetransmitting mechanisms 1564, 1565, 1569 and 1570 comprise brakingsynchronizers, and the torque transmitting mechanisms 1567, 1568, 1571and 1572 comprise rotating synchronizers.

Accordingly, the input shaft 17 is alternately connected with the firstand second transmission subsets 1560, 1561 (i.e. through the clutch 1562to synchronizers 1567, 1568 and through the clutch 1563 to the sun gearmember 1542). The sun gear member 1522 is continuously connected withthe ring gear member 1534 through the interconnecting member 1574. Theplanet carrier assembly member 1526 is continuously connected with thesun gear member 1532 through the interconnecting member 1576. The planetcarrier assembly member 1546 is continuously connected with the planetcarrier assembly member 1536 and the output shaft 19 through theinterconnecting member 1578. The ring gear member 1544 is continuouslyconnected with the sun gear member 1552 through the interconnectingmember 1579.

The ring gear member 1524 is selectively connectable with thetransmission housing 1580 through the braking synchronizer 1564. Thering gear member 1534 is selectively connectable with the transmissionhousing 1580 through the braking synchronizer 1565. The ring gear member1524 is selectively connectable with the input shaft 17 through theinput clutch 1562 and the rotating synchronizer 1567. The sun gearmember 1532 is selectively connectable with the input shaft 17 throughthe input clutch 1562 and the rotating synchronizer 1568. The ring gearmember 1554 is selectively connectable with the transmission housing1580 through the braking synchronizer 1569. The planet carrier assemblymember 1556 is selectively connectable with the transmission housing1580 through the braking synchronizer 1570. The planet carrier assemblymember 1546 is selectively connectable with the ring gear member 1554through the rotating synchronizer 1571. The planet carrier assemblymember 1546 is selectively connectable with the planet carrier assemblymember 1556 through the rotating synchronizer 1572.

As shown in FIG. 16b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide five forwardspeed ratios and a reverse speed ratio. The chart of FIG. 16b describesthe ratio steps between adjacent forward speed ratios and the ratio stepbetween the reverse and first forward speed ratio.

Those skilled in the art, upon reviewing the truth table and theschematic representation of FIG. 6a can determine that the numericalvalues of the reverse and fourth forward speed ratios are determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets1520, 1530. The numerical value of the first forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 1540, 1550. The numerical value of the secondforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 1530. The numerical value of the thirdforward speed ratio is determined utilizing the ring gear/sun gear toothratio of the planetary gear set 1540. The numerical value of the fifthforward speed ratio is 1.

The sample speed ratios given in the truth table are determinedutilizing the tooth ratio values also given in FIG. 16b. R1/S1 value isthe tooth ratio of the planetary gear set 1520; the R2/S2 value is thetooth ratio of the planetary gear set 1530; the R3/S3 value is the toothratio of the planetary gear set 1540; and the R4/S4 value is the toothratio of the planetary gear set 1550.

While the best modes for carrying out the invention have been describedin detail, those familiar with the art to which this invention relateswill recognize various alternative designs and embodiments forpracticing the invention within the scope of the appended claims.

What is claimed is:
 1. A multi-speed transmission comprising: an inputshaft; an output shaft; first, second, third and fourth planetary gearsets each having first, second and third members; a firstinterconnecting member continuously interconnecting said first member ofsaid first planetary gear set with said first member of said secondplanetary gear set; a second interconnecting member continuouslyinterconnecting said second member of said first planetary gear set withsaid second member of said second planetary gear set; a thirdinterconnecting member continuously interconnecting said third member ofsaid second planetary gear set with said first member of said thirdplanetary gear set and said output shaft; a fourth interconnectingmember continuously interconnecting said second member of said thirdplanetary gear set with said first member of said fourth planetary gearset; a first input clutch selectively interconnecting said input shaftwith said third member of said third planetary gear set; first andsecond torque-transmitting mechanisms selectively engageable tointerconnect said first and third members of said first planetary gearset, respectively, and said input shaft; third and fourthtorque-transmitting mechanisms for selectively interconnecting saidfirst member of said third planetary gear set with said second and thirdmembers of said fourth planetary gear set, respectively; fifth and sixthtorque-transmitting mechanisms for selectively interconnecting two ofsaid members of said first planetary gear set with a stationary member,respectively; a seventh torque-transmitting mechanism selectivelyinterconnecting said second member of said fourth planetary gear setwith said stationary member; an eighth torque-transmitting mechanism,said eighth torque-transmitting mechanism selectively interconnectingsaid third member of said fourth planetary gear set with said stationarymember, or said eighth torque-transmitting mechanism selectivelyinterconnecting a member of said first planetary gear set with one ofsaid input shaft or said stationary member; and said first input clutchand torque-transmitting mechanisms being engaged in combinations of atleast three to provide at least five forward speed ratios and a reversespeed ratio.
 2. The transmission defined in claim 1, wherein saidtorque-transmitting mechanisms comprise synchronizers.
 3. Thetransmission defined in claim 1, further comprising a second inputclutch connected with said input shaft, wherein said second input clutchis applied for odd number speed ranges and said first input clutch isapplied for even number speed ranges.
 4. The transmission defined inclaim 1, further comprising a second input clutch connected with saidinput shaft, wherein said second input clutch is applied for even numberspeed ranges and said first input clutch is applied for odd number speedranges.
 5. The transmission defined in claim 1, further comprising asecond input clutch connected with said input shaft, wherein said secondinput clutch and said first input clutch are interchangeable to shiftfrom odd number speed ranges to even number speed ranges, and viceversa.
 6. The transmission defined in claim 1, wherein selected ones ofsaid torque-transmitting mechanisms are engaged prior to gear shiftingto achieve shifting without torque interruptions.
 7. The transmissiondefined in claim 2, wherein at least two of said synchronizers comprisea double synchronizer to reduce cost and package size.
 8. Thetransmission defined in claim 1, wherein further comprising a secondinput clutch, and wherein said first and second torque-transmittingmechanisms indirectly interconnect said first and third members of saidfirst planetary gear set, respectively, with said input shaft via saidsecond input clutch.
 9. The transmission defined in claim 1, whereineach planetary gear set comprises a sun gear member, a ring gear memberand a planet carrier assembly member, and wherein planet carrierassembly members of a plurality of said planetary gear sets are singlepinion carriers.
 10. The transmission defined in claim 1, wherein eachplanetary gear set comprises a sun gear member, a ring gear member and aplanet carrier assembly member, and wherein planet carrier assemblymembers of a plurality of said planetary gear sets are double pinioncarriers.
 11. The transmission defined in claim 1, further comprising: aninth torque-transmitting mechanism; wherein said eighthtorque-transmitting mechanism selectively interconnects said thirdmember of said fourth planetary gear set with said stationary member;and wherein said ninth torque-transmitting mechanism selectivelyinterconnects a member of said first planetary gear set with one of saidinput shaft or said stationary member.
 12. The transmission define inclaim 11, wherein said first, second and ninth torque-transmittingmechanisms are selectively engageable to directly interconnect saidinput shaft.
 13. The transmission defined in claim 1, further comprisinga second input clutch; and wherein said input clutches andtorque-transmitting mechanisms are engaged in combinations of at leastthree to establish at least five forward speed ratios and a reversespeed ratio between said input shaft and said output shaft.
 14. Thetransmission defined in claim 11, wherein said first, second, third,fourth and ninth torque-transmitting mechanisms comprise rotatingsynchronizers, and said fifth, sixth, seventh and eighthtorque-transmitting mechanisms comprise braking synchronizers.
 15. Thetransmission defined in claim 11, wherein said first, second, third andfourth torque transmitting mechanisms comprise rotating synchronizers,and said fifth, sixth, seventh, eighth and ninth torque transmittingmechanisms comprise braking synchronizers.
 16. The transmission definedin claim 11, wherein said first and second torque-transmittingmechanisms are selectively engageable to directly interconnect saidfirst and third members of said first planetary gear set, respectively,with said input shaft, and said ninth torque-transmitting mechanismselectively interconnects said member of said first planetary gear setwith said stationary member.
 17. The transmission defined in claim 12,wherein said torque-transmitting mechanisms and first input clutch areengaged in combinations of at least three to establish at least fiveforward speed ratios and a reverse speed ratio between said input shaftand said output shaft.
 18. The transmission defined in claim 16, whereinsaid torque-transmitting mechanisms and first input clutch are engagedin combinations of at least three to establish at least five forwardspeed ratios and a reverse speed ratio between said input shaft and saidoutput shaft.
 19. A multi-speed transmission comprising: an input shaft;an output shaft; first, second, third and fourth planetary gear setseach having first, second and third members; a first interconnectingmember continuously interconnecting said first member of said firstplanetary gear set with said first member of said second planetary gearset; a second interconnecting member continuously interconnecting saidsecond member of said first planetary gear set with said second memberof said second planetary gear set; a third interconnecting membercontinuously interconnecting said third member of said second planetarygear set with said first member of said third planetary gear set andsaid output shaft; a fourth interconnecting member continuouslyinterconnecting said second member of said third planetary gear set withsaid first member of said fourth planetary gear set; a first inputclutch selectively interconnecting said input shaft with said thirdmember of said third planetary gear set; and at least eighttorque-transmitting mechanisms for selectively interconnecting saidmembers of said first, second, third or fourth planetary gear sets witha stationary member, with said input shaft, or in pairs for commonrotation, said first input clutch and torque-transmitting mechanismsbeing engaged in combinations of at least three to establish at leastfive forward speed ratios and a reverse speed ratio between said inputshaft and said output shaft.
 20. The transmission defined in claim 19,further comprising a second input clutch connected with said inputshaft, wherein first and second of said torque-transmitting mechanismsare selectively operable for interconnecting said first and thirdmembers of said first planetary gear set with said second input clutch,respectively.
 21. The transmission defined in claim 19, wherein thirdand fourth of said torque-transmitting mechanisms are selectivelyoperable for interconnecting said first member of said third planetarygear set with said second and third members of said fourth planetarygear set, respectively.
 22. The transmission defined in claim 19,wherein fifth and sixth of said torque-transmitting mechanisms areoperable for selectively interconnecting two of said members of saidfirst planetary gear set with said stationary member, respectively. 23.The transmission defined in claim 19, wherein seventh and eighth of saidtorque-transmitting mechanisms are operable for selectivelyinterconnecting said second and third members of said fourth planetarygear set with said stationary member, respectively.
 24. The transmissiondefined in claim 19, further comprising a second input clutch connectedwith said input shaft, wherein a ninth of said torque-transmittingmechanisms is selectively operable for interconnecting a member of saidfirst planetary gear set with one of said second input clutch or saidstationary member.
 25. The transmission defined in claim 19, whereineach planetary gear set comprises a sun gear member, a ring gear memberand a planet carrier assembly member, and wherein planet carrierassembly members of a plurality of said planetary gear sets are singlepinion carriers.
 26. The transmission defined in claim 19, wherein eachplanetary gear set comprises a sun gear member, a ring gear member and aplanet carrier assembly member, and wherein planet carrier assemblymembers of a plurality of said planetary gear sets are double pinioncarriers.
 27. The transmission defined in claim 19, wherein each of saidtorque-transmitting mechanisms comprises a synchronizer.
 28. Thetransmission defined in claim 19, further comprising a second inputclutch connected with said input shaft, wherein at least one of a firstor a second of said torque-transmitting mechanisms or said second inputclutch is applied for odd number speed ranges and said first inputclutch is applied for even number speed ranges.
 29. The transmissiondefined in claim 19, further comprising a second input clutch connectedwith said input shaft, wherein at least one of a first or a second ofsaid torque-transmitting mechanisms or said second input clutch isapplied for even number speed ranges and said first input clutch isapplied for odd number speed ranges.
 30. The transmission defined inclaim 19, wherein selected ones of said torque-transmitting mechanismsare engaged prior to gear shifting to achieve shifting without torqueinterruptions.
 31. The transmission defined in claim 19, wherein afirst, second and ninth of said torque-transmitting mechanisms areselectively engageable to directly interconnect said input shaft. 32.The transmission defined in claim 19, wherein first and second of saidtorque-transmitting mechanisms are selectively engageable to directlyinterconnect said members of said gear sets with said input shaft, and aninth of said torque-transmitting mechanisms is selectively engageableto connect said members of said gear sets with said stationary member.33. The transmission defined in claim 19, further comprising a secondinput clutch, and wherein said input clutches and torque-transmittingmechanisms are engaged in combinations of at least three to establish atleast five forward speed ratios and a reverse speed ratio between saidinput shaft and said output shaft.
 34. The transmission defined in claim31, wherein torque-transmitting mechanisms and first input clutch areengaged in combinations of at least three to establish at least fiveforward speed ratios and a reverse speed ratio between said input shaftand said output shaft.
 35. The transmission defined in claim 32, whereinsaid torque-transmitting mechanisms and first input clutch are engagedin combinations of at least three to establish at least five forwardspeed ratios and a reverse speed ratio between said input shaft and saidoutput shaft.